--- a/accessible/ipc/win/DocAccessibleChild.cpp
+++ b/accessible/ipc/win/DocAccessibleChild.cpp
@@ -269,16 +269,36 @@ DocAccessibleChild::SendRoleChangedEvent
     return PDocAccessibleChild::SendRoleChangedEvent(aRole);
   }
 
   PushDeferredEvent(MakeUnique<SerializedRoleChanged>(this, aRole));
   return true;
 }
 
 bool
+DocAccessibleChild::SendScrollingEvent(const uint64_t& aID,
+                                       const uint64_t& aType,
+                                       const uint32_t& aScrollX,
+                                       const uint32_t& aScrollY,
+                                       const uint32_t& aMaxScrollX,
+                                       const uint32_t& aMaxScrollY)
+{
+  if (IsConstructedInParentProcess()) {
+    return PDocAccessibleChild::SendScrollingEvent(aID, aType,
+                                                   aScrollX, aScrollY,
+                                                   aMaxScrollX, aMaxScrollY);
+  }
+
+  PushDeferredEvent(MakeUnique<SerializedScrolling>(this, aID, aType,
+                                                    aScrollX, aScrollY,
+                                                    aMaxScrollX, aMaxScrollY));
+  return true;
+}
+
+bool
 DocAccessibleChild::ConstructChildDocInParentProcess(
                                         DocAccessibleChild* aNewChildDoc,
                                         uint64_t aUniqueID, uint32_t aMsaaID)
 {
   if (IsConstructedInParentProcess()) {
     // We may send the constructor immediately
     auto tabChild = static_cast<dom::TabChild*>(Manager());
     MOZ_ASSERT(tabChild);

--- a/accessible/ipc/win/DocAccessibleChild.h
+++ b/accessible/ipc/win/DocAccessibleChild.h
@@ -53,16 +53,20 @@ public:
                       const LayoutDeviceIntRect& aCaretRect);
   bool SendTextChangeEvent(const uint64_t& aID, const nsString& aStr,
                            const int32_t& aStart, const uint32_t& aLen,
                            const bool& aIsInsert, const bool& aFromUser,
                            const bool aDoSyncCheck = true);
   bool SendSelectionEvent(const uint64_t& aID, const uint64_t& aWidgetID,
                           const uint32_t& aType);
   bool SendRoleChangedEvent(const a11y::role& aRole);
+  bool SendScrollingEvent(const uint64_t& aID, const uint64_t& aType,
+                          const uint32_t& aScrollX, const uint32_t& aScrollY,
+                          const uint32_t& aMaxScrollX,
+                          const uint32_t& aMaxScrollY);
 
   bool ConstructChildDocInParentProcess(DocAccessibleChild* aNewChildDoc,
                                         uint64_t aUniqueID, uint32_t aMsaaID);
 
   bool SendBindChildDoc(DocAccessibleChild* aChildDoc,
                         const uint64_t& aNewParentID);
 
 protected:
@@ -264,16 +268,45 @@ private:
     void Dispatch(DocAccessibleChild* aIPCDoc) override
     {
       Unused << aIPCDoc->SendRoleChangedEvent(mRole);
     }
 
     a11y::role mRole;
   };
 
+  struct SerializedScrolling final : public DeferredEvent
+  {
+    explicit SerializedScrolling(DocAccessibleChild* aTarget,
+                                 uint64_t aID, uint64_t aType,
+                                 uint32_t aScrollX, uint32_t aScrollY,
+                                 uint32_t aMaxScrollX, uint32_t aMaxScrollY)
+      : DeferredEvent(aTarget)
+      , mID(aID)
+      , mType(aType)
+      , mScrollX(aScrollX)
+      , mScrollY(aScrollY)
+      , mMaxScrollX(aMaxScrollX)
+      , mMaxScrollY(aMaxScrollY)
+    {}
+
+    void Dispatch(DocAccessibleChild* aIPCDoc) override
+    {
+      Unused << aIPCDoc->SendScrollingEvent(mID, mType, mScrollX, mScrollY,
+                                            mMaxScrollX, mMaxScrollY);
+    }
+
+    uint64_t mID;
+    uint64_t mType;
+    uint32_t mScrollX;
+    uint32_t mScrollY;
+    uint32_t mMaxScrollX;
+    uint32_t mMaxScrollY;
+  };
+
   struct SerializedEvent final : public DeferredEvent
   {
     SerializedEvent(DocAccessibleChild* aTarget, uint64_t aID, uint32_t aType)
       : DeferredEvent(aTarget)
       , mID(aID)
       , mType(aType)
     {}
 

--- a/browser/base/content/tabbrowser.js
+++ b/browser/base/content/tabbrowser.js
@@ -770,42 +770,48 @@ window._gBrowser = {
       ).URI;
       return resolvedURI.schemeIs("jar") || resolvedURI.schemeIs("file");
     } catch (ex) {
       // aURI might be invalid.
       return false;
     }
   },
 
-  setIcon(aTab, aIconURL = "", aOriginalURL = aIconURL) {
+  setIcon(aTab, aIconURL = "", aOriginalURL = aIconURL, aLoadingPrincipal = null) {
     let makeString = (url) => url instanceof Ci.nsIURI ? url.spec : url;
 
     aIconURL = makeString(aIconURL);
     aOriginalURL = makeString(aOriginalURL);
 
     let LOCAL_PROTOCOLS = [
       "chrome:",
       "about:",
       "resource:",
       "data:",
     ];
 
-    if (aIconURL && !LOCAL_PROTOCOLS.some(protocol => aIconURL.startsWith(protocol))) {
-      console.error(`Attempt to set a remote URL ${aIconURL} as a tab icon.`);
+    if (aIconURL && !aLoadingPrincipal && !LOCAL_PROTOCOLS.some(protocol => aIconURL.startsWith(protocol))) {
+      console.error(`Attempt to set a remote URL ${aIconURL} as a tab icon without a loading principal.`);
       return;
     }
 
     let browser = this.getBrowserForTab(aTab);
     browser.mIconURL = aIconURL;
 
     if (aIconURL != aTab.getAttribute("image")) {
       if (aIconURL) {
+        if (aLoadingPrincipal) {
+          aTab.setAttribute("iconloadingprincipal", aLoadingPrincipal);
+        } else {
+          aTab.removeAttribute("iconloadingprincipal");
+        }
         aTab.setAttribute("image", aIconURL);
       } else {
         aTab.removeAttribute("image");
+        aTab.removeAttribute("iconloadingprincipal");
       }
       this._tabAttrModified(aTab, ["image"]);
     }
 
     // The aOriginalURL argument is currently only used by tests.
     this._callProgressListeners(browser, "onLinkIconAvailable", [aIconURL, aOriginalURL]);
   },
 

--- a/browser/base/content/test/chrome/test_aboutRestartRequired.xul
+++ b/browser/base/content/test/chrome/test_aboutRestartRequired.xul
@@ -8,17 +8,16 @@
 
 <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
   <script type="application/javascript"
           src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
   <iframe type="content" id="frame1"/>
   <iframe type="content" id="frame2" onload="doTest()"/>
   <script type="application/javascript"><![CDATA[
     ChromeUtils.import("resource://gre/modules/Services.jsm");
-    ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 
     SimpleTest.waitForExplicitFinish();
 
     // Load error pages do not fire "load" events, so let's use a progressListener.
     function waitForErrorPage(frame) {
       return new Promise(resolve => {
         let progressListener = {
           onLocationChange: function(aWebProgress, aRequest, aLocation, aFlags) {
@@ -27,18 +26,18 @@
                             .getInterface(Ci.nsIWebProgress)
                             .removeProgressListener(progressListener,
                                                     Ci.nsIWebProgress.NOTIFY_LOCATION);
 
               resolve();
             }
           },
 
-          QueryInterface: XPCOMUtils.generateQI([Ci.nsIWebProgressListener,
-                                                 Ci.nsISupportsWeakReference])
+          QueryInterface: ChromeUtils.generateQI([Ci.nsIWebProgressListener,
+                                                  Ci.nsISupportsWeakReference])
         };
 
         frame.docShell.QueryInterface(Ci.nsIInterfaceRequestor)
                       .getInterface(Ci.nsIWebProgress)
                       .addProgressListener(progressListener,
                                            Ci.nsIWebProgress.NOTIFY_LOCATION);
       });
     }

--- a/browser/components/payments/content/paymentDialogFrameScript.js
+++ b/browser/components/payments/content/paymentDialogFrameScript.js
@@ -71,18 +71,18 @@ let PaymentFrameScript = {
    * Expose privileged utility functions to the unprivileged page.
    */
   exposeUtilityFunctions() {
     let waivedContent = Cu.waiveXrays(content);
     let PaymentDialogUtils = {
       DEFAULT_REGION: FormAutofill.DEFAULT_REGION,
       supportedCountries: FormAutofill.supportedCountries,
 
-      getAddressLabel(address) {
-        return FormAutofillUtils.getAddressLabel(address);
+      getAddressLabel(address, addressFields = null) {
+        return FormAutofillUtils.getAddressLabel(address, addressFields);
       },
 
       isCCNumber(value) {
         return FormAutofillUtils.isCCNumber(value);
       },
 
       getFormFormat(country) {
         let format = FormAutofillUtils.getFormFormat(country);

--- a/browser/components/payments/res/components/address-option.js
+++ b/browser/components/payments/res/components/address-option.js
@@ -52,18 +52,18 @@ export default class AddressOption exten
 
   connectedCallback() {
     for (let name of ["name", "street-address", "email", "tel"]) {
       this.appendChild(this[`_${name}`]);
     }
     super.connectedCallback();
   }
 
-  static formatSingleLineLabel(address) {
-    return PaymentDialogUtils.getAddressLabel(address);
+  static formatSingleLineLabel(address, addressFields) {
+    return PaymentDialogUtils.getAddressLabel(address, addressFields);
   }
 
   render() {
     // Fall back to empty strings to prevent 'null' from appearing.
     this._name.textContent = this.name || "";
     this["_street-address"].textContent =
       `${this.streetAddress || ""} ${this.addressLevel2 || ""} ` +
       `${this.addressLevel1 || ""} ${this.postalCode || ""} ${this.country || ""}`;

--- a/browser/components/payments/res/containers/address-picker.js
+++ b/browser/components/payments/res/containers/address-picker.js
@@ -95,17 +95,20 @@ export default class AddressPicker exten
         let val = address[key];
         if (val) {
           optionEl.setAttribute(key, val);
         } else {
           optionEl.removeAttribute(key);
         }
       }
 
-      optionEl.textContent = AddressOption.formatSingleLineLabel(address);
+      // fieldNames getter is not used here because it returns a default array with
+      // attributes even when "address-fields" observed attribute is null.
+      let addressFields = this.getAttribute("address-fields");
+      optionEl.textContent = AddressOption.formatSingleLineLabel(address, addressFields);
       desiredOptions.push(optionEl);
     }
 
     this.dropdown.popupBox.textContent = "";
     for (let option of desiredOptions) {
       this.dropdown.popupBox.appendChild(option);
     }
 

--- a/browser/components/payments/res/unprivileged-fallbacks.js
+++ b/browser/components/payments/res/unprivileged-fallbacks.js
@@ -17,17 +17,22 @@
 var log = {
   error: console.error.bind(console, "paymentRequest.xhtml:"),
   warn: console.warn.bind(console, "paymentRequest.xhtml:"),
   info: console.info.bind(console, "paymentRequest.xhtml:"),
   debug: console.debug.bind(console, "paymentRequest.xhtml:"),
 };
 
 var PaymentDialogUtils = {
-  getAddressLabel(address) {
+  getAddressLabel(address, addressFields = null) {
+    if (addressFields) {
+      let requestedFields = addressFields.trim().split(/\s+/);
+      return requestedFields.filter(f => f && address[f]).map(f => address[f]).join(", ") +
+        ` (${address.guid})`;
+    }
     return `${address.name} (${address.guid})`;
   },
   isCCNumber(str) {
     return !!str.replace(/[-\s]/g, "").match(/^\d{9,}$/);
   },
   DEFAULT_REGION: "US",
   supportedCountries: ["US", "CA"],
   getFormFormat(country) {

--- a/browser/components/payments/test/browser/browser_address_edit.js
+++ b/browser/components/payments/test/browser/browser_address_edit.js
@@ -370,16 +370,99 @@ add_task(async function test_edit_payer_
 
     info("clicking cancel");
     spawnPaymentDialogTask(frame, PTU.DialogContentTasks.manuallyClickCancel);
 
     await BrowserTestUtils.waitForCondition(() => win.closed, "dialog should be closed");
   });
 });
 
+add_task(async function test_shipping_address_picker() {
+  await setup();
+  await BrowserTestUtils.withNewTab({
+    gBrowser,
+    url: BLANK_PAGE_URL,
+  }, async browser => {
+    let {win, frame} =
+      await setupPaymentDialog(browser, {
+        methodData: [PTU.MethodData.basicCard],
+        details: PTU.Details.total60USD,
+        options: PTU.Options.requestShippingOption,
+        merchantTaskFn: PTU.ContentTasks.createAndShowRequest,
+      }
+    );
+
+    await spawnPaymentDialogTask(frame, async function test_picker_option_label(address) {
+      let {
+        PaymentTestUtils: PTU,
+      } = ChromeUtils.import("resource://testing-common/PaymentTestUtils.jsm", {});
+      ChromeUtils.import("resource://formautofill/FormAutofillUtils.jsm");
+
+      let state = await PTU.DialogContentUtils.waitForState(content, (state) => {
+        return Object.keys(state.savedAddresses).length == 1;
+      }, "One saved addresses when starting test");
+      let savedAddress = Object.values(state.savedAddresses)[0];
+
+      let selector = "address-picker[selected-state-key='selectedShippingAddress']";
+      let picker = content.document.querySelector(selector);
+      let option = Cu.waiveXrays(picker).dropdown.popupBox.children[0];
+      ok(option.textContent,
+         FormAutofillUtils.getAddressLabel(savedAddress, null),
+         "Shows correct shipping option label");
+    });
+
+    info("clicking cancel");
+    spawnPaymentDialogTask(frame, PTU.DialogContentTasks.manuallyClickCancel);
+
+    await BrowserTestUtils.waitForCondition(() => win.closed, "dialog should be closed");
+  });
+});
+
+add_task(async function test_payer_address_picker() {
+  await BrowserTestUtils.withNewTab({
+    gBrowser,
+    url: BLANK_PAGE_URL,
+  }, async browser => {
+    let {win, frame} =
+      await setupPaymentDialog(browser, {
+        methodData: [PTU.MethodData.basicCard],
+        details: PTU.Details.total60USD,
+        options: PTU.Options.requestPayerNameEmailAndPhone,
+        merchantTaskFn: PTU.ContentTasks.createAndShowRequest,
+      }
+    );
+
+    await spawnPaymentDialogTask(frame, async function test_picker_option_label(address) {
+      let {
+        PaymentTestUtils: PTU,
+      } = ChromeUtils.import("resource://testing-common/PaymentTestUtils.jsm", {});
+      ChromeUtils.import("resource://formautofill/FormAutofillUtils.jsm");
+
+      let state = await PTU.DialogContentUtils.waitForState(content, (state) => {
+        return Object.keys(state.savedAddresses).length == 1;
+      }, "One saved addresses when starting test");
+      let savedAddress = Object.values(state.savedAddresses)[0];
+
+      let selector = "address-picker[selected-state-key='selectedPayerAddress']";
+      let picker = content.document.querySelector(selector);
+      let option = Cu.waiveXrays(picker).dropdown.popupBox.children[0];
+      is(option.textContent.includes("32 Vassar Street"), false,
+         "Payer option label does not contain street address");
+      ok(option.textContent,
+         FormAutofillUtils.getAddressLabel(savedAddress, "name tel email"),
+         "Shows correct payer option label");
+    });
+
+    info("clicking cancel");
+    spawnPaymentDialogTask(frame, PTU.DialogContentTasks.manuallyClickCancel);
+
+    await BrowserTestUtils.waitForCondition(() => win.closed, "dialog should be closed");
+  });
+});
+
 /*
  * Test that we can correctly add an address from a private window
  */
 add_task(async function test_private_persist_addresses() {
   let prefilledGuids = await setup();
 
   is((await formAutofillStorage.addresses.getAll()).length, 1,
      "Setup results in 1 stored address at start of test");

--- a/browser/components/sessionstore/SessionStore.jsm
+++ b/browser/components/sessionstore/SessionStore.jsm
@@ -1977,17 +1977,16 @@ var SessionStoreInternal = {
     let tabTitle = aTab.label;
     let {permanentKey} = aTab.linkedBrowser;
 
     let tabData = {
       permanentKey,
       state: tabState,
       title: tabTitle,
       image: tabbrowser.getIcon(aTab),
-      iconLoadingPrincipal: Utils.serializePrincipal(aTab.linkedBrowser.contentPrincipal),
       pos: aTab._tPos,
       closedAt: Date.now()
     };
 
     let closedTabs = this._windows[aWindow.__SSi]._closedTabs;
 
     // Determine whether the tab contains any information worth saving. Note
     // that there might be pending state changes queued in the child that
@@ -2774,19 +2773,17 @@ var SessionStoreInternal = {
         win.gBrowser.setInitialTabTitle(tab, activePageData.title, { isContentTitle: true });
       } else if (activePageData.url != "about:blank") {
         win.gBrowser.setInitialTabTitle(tab, activePageData.url);
       }
     }
 
     // Restore the tab icon.
     if ("image" in tabData) {
-      // Use the serialized contentPrincipal with the new icon load.
-      let loadingPrincipal = Utils.deserializePrincipal(tabData.iconLoadingPrincipal);
-      win.gBrowser.setIcon(tab, tabData.image, loadingPrincipal);
+      win.gBrowser.setIcon(tab, tabData.image, undefined, tabData.iconLoadingPrincipal);
       TabStateCache.update(browser, { image: null, iconLoadingPrincipal: null });
     }
   },
 
   // This method deletes all the closedTabs matching userContextId.
   _forgetTabsWithUserContextId(userContextId) {
     let windowsEnum = Services.wm.getEnumerator("navigator:browser");
     while (windowsEnum.hasMoreElements()) {

--- a/browser/components/sessionstore/TabAttributes.jsm
+++ b/browser/components/sessionstore/TabAttributes.jsm
@@ -7,20 +7,17 @@
 var EXPORTED_SYMBOLS = ["TabAttributes"];
 
 // We never want to directly read or write these attributes.
 // 'image' should not be accessed directly but handled by using the
 //         gBrowser.getIcon()/setIcon() methods.
 // 'muted' should not be accessed directly but handled by using the
 //         tab.linkedBrowser.audioMuted/toggleMuteAudio methods.
 // 'pending' is used internal by sessionstore and managed accordingly.
-// 'iconloadingprincipal' is same as 'image' that it should be handled by
-//                        using the gBrowser.getIcon()/setIcon() methods.
-const ATTRIBUTES_TO_SKIP = new Set(["image", "muted", "pending", "iconloadingprincipal",
-                                    "skipbackgroundnotify"]);
+const ATTRIBUTES_TO_SKIP = new Set(["image", "muted", "pending", "skipbackgroundnotify"]);
 
 // A set of tab attributes to persist. We will read a given list of tab
 // attributes when collecting tab data and will re-set those attributes when
 // the given tab data is restored to a new tab.
 var TabAttributes = Object.freeze({
   persist(name) {
     return TabAttributesInternal.persist(name);
   },

--- a/browser/components/sessionstore/TabState.jsm
+++ b/browser/components/sessionstore/TabState.jsm
@@ -7,18 +7,16 @@
 var EXPORTED_SYMBOLS = ["TabState"];
 
 ChromeUtils.defineModuleGetter(this, "PrivacyFilter",
   "resource://gre/modules/sessionstore/PrivacyFilter.jsm");
 ChromeUtils.defineModuleGetter(this, "TabStateCache",
   "resource:///modules/sessionstore/TabStateCache.jsm");
 ChromeUtils.defineModuleGetter(this, "TabAttributes",
   "resource:///modules/sessionstore/TabAttributes.jsm");
-ChromeUtils.defineModuleGetter(this, "Utils",
-  "resource://gre/modules/sessionstore/Utils.jsm");
 
 /**
  * Module that contains tab state collection methods.
  */
 var TabState = Object.freeze({
   update(browser, data) {
     TabStateInternal.update(browser, data);
   },
@@ -120,21 +118,16 @@ var TabStateInternal = {
     // be read from the tab/browser every time we collect data.
 
     // Store the tab icon.
     if (!("image" in tabData)) {
       let tabbrowser = tab.ownerGlobal.gBrowser;
       tabData.image = tabbrowser.getIcon(tab);
     }
 
-    // Store the serialized contentPrincipal of this tab to use for the icon.
-    if (!("iconLoadingPrincipal" in tabData)) {
-      tabData.iconLoadingPrincipal = Utils.serializePrincipal(browser.mIconLoadingPrincipal);
-    }
-
     // If there is a userTypedValue set, then either the user has typed something
     // in the URL bar, or a new tab was opened with a URI to load.
     // If so, we also track whether we were still in the process of loading something.
     if (!("userTypedValue" in tabData) && browser.userTypedValue) {
       tabData.userTypedValue = browser.userTypedValue;
       // We always used to keep track of the loading state as an integer, where
       // '0' indicated the user had typed since the last load (or no load was
       // ongoing), and any positive value indicated we had started a load since

--- a/browser/components/sessionstore/test/browser.ini
+++ b/browser/components/sessionstore/test/browser.ini
@@ -52,16 +52,17 @@ support-files =
   browser_911547_sample.html^headers^
   restore_redirect_http.html
   restore_redirect_http.html^headers^
   restore_redirect_js.html
   restore_redirect_target.html
   browser_1234021_page.html
   browser_1284886_suspend_tab.html
   browser_1284886_suspend_tab_2.html
+  empty.html
 
 #NB: the following are disabled
 #  browser_464620_a.html
 #  browser_464620_b.html
 #  browser_464620_xd.html
 
 
 #disabled-for-intermittent-failures--bug-766044, browser_459906_empty.html
@@ -102,16 +103,17 @@ skip-if = (verify && debug)
 [browser_formdata_xpath.js]
 [browser_frametree.js]
 [browser_frame_history.js]
 skip-if = (verify && (os == 'win' || os == 'mac'))
 [browser_global_store.js]
 [browser_history_persist.js]
 [browser_label_and_icon.js]
 [browser_merge_closed_tabs.js]
+[browser_old_favicon.js]
 [browser_page_title.js]
 [browser_pending_tabs.js]
 [browser_privatetabs.js]
 [browser_purge_shistory.js]
 skip-if = e10s # Bug 1271024
 [browser_replace_load.js]
 [browser_restore_redirect.js]
 [browser_restore_cookies_noOriginAttributes.js]

new file mode 100644
--- /dev/null
+++ b/browser/components/sessionstore/test/browser_old_favicon.js
@@ -0,0 +1,44 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Ensure that we can restore old style favicon and principals.
+ */
+add_task(async function test_label_and_icon() {
+  let helper = Cc["@mozilla.org/network/serialization-helper;1"].getService(Ci.nsISerializationHelper);
+
+  // Make sure that tabs are restored on demand as otherwise the tab will start
+  // loading immediately and override the icon.
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.sessionstore.restore_on_demand", true]],
+  });
+
+  // Create a new tab.
+  let tab = BrowserTestUtils.addTab(gBrowser, "http://www.example.com/browser/browser/components/sessionstore/test/empty.html");
+  let browser = tab.linkedBrowser;
+  await promiseBrowserLoaded(browser);
+
+  let contentPrincipal = browser.contentPrincipal;
+  let serializedPrincipal = helper.serializeToString(contentPrincipal);
+
+  // Retrieve the tab state.
+  await TabStateFlusher.flush(browser);
+  let state = JSON.parse(ss.getTabState(tab));
+  state.image = "http://www.example.com/favicon.ico";
+  state.iconLoadingPrincipal = serializedPrincipal;
+
+  BrowserTestUtils.removeTab(tab);
+
+  // Open a new tab to restore into.
+  tab = BrowserTestUtils.addTab(gBrowser, "about:blank");
+  ss.setTabState(tab, state);
+  await promiseTabRestoring(tab);
+
+  // Check that label and icon are set for the restoring tab.
+  is(gBrowser.getIcon(tab), "http://www.example.com/favicon.ico", "icon is set");
+  is(tab.getAttribute("image"), "http://www.example.com/favicon.ico", "tab image is set");
+  is(tab.getAttribute("iconloadingprincipal"), serializedPrincipal, "tab image loading principal is set");
+
+  // Cleanup.
+  BrowserTestUtils.removeTab(tab);
+});

new file mode 100644
--- /dev/null
+++ b/browser/components/sessionstore/test/empty.html
@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+
+<html>
+  <body>
+  </body>
+</html>

--- a/browser/config/mozconfigs/linux64/plain-opt
+++ b/browser/config/mozconfigs/linux64/plain-opt
@@ -4,13 +4,13 @@ export LLVM_CONFIG="${TOOLTOOL_DIR}/clan
 CARGO="${TOOLTOOL_DIR}/rustc/bin/cargo"
 RUSTC="${TOOLTOOL_DIR}/rustc/bin/rustc"
 RUSTDOC="${TOOLTOOL_DIR}/rustc/bin/rustdoc"
 RUSTFMT="${TOOLTOOL_DIR}/rustc/bin/rustfmt"
 CBINDGEN="${TOOLTOOL_DIR}/cbindgen/cbindgen"
 
 export NODEJS="${TOOLTOOL_DIR}/node/bin/node"
 
-CC="${TOOLTOOL_DIR}/gcc/bin/gcc"
-CXX="${TOOLTOOL_DIR}/gcc/bin/g++"
+CC="${TOOLTOOL_DIR}/clang/bin/clang"
+CXX="${TOOLTOOL_DIR}/clang/bin/clang++"
 
 mk_add_options "export PATH=${TOOLTOOL_DIR}/gcc/bin:${PATH}"
 mk_add_options "export LD_LIBRARY_PATH=${TOOLTOOL_DIR}/gcc/lib64:${TOOLTOOL_DIR}/gcc/lib32:${TOOLTOOL_DIR}/gcc/lib"

--- a/browser/extensions/formautofill/FormAutofillUtils.jsm
+++ b/browser/extensions/formautofill/FormAutofillUtils.jsm
@@ -241,51 +241,56 @@ this.FormAutofillUtils = {
 
   getAddressSeparator() {
     // The separator should be based on the L10N address format, and using a
     // white space is a temporary solution.
     return " ";
   },
 
   /**
-   * Get address display label. It should display up to two pieces of
-   * information, separated by a comma.
+   * Get address display label. It should display information separated
+   * by a comma.
    *
    * @param  {object} address
+   * @param  {string?} addressFields Override the fields which can be displayed, but not the order.
    * @returns {string}
    */
-  getAddressLabel(address) {
+  getAddressLabel(address, addressFields = null) {
     // TODO: Implement a smarter way for deciding what to display
     //       as option text. Possibly improve the algorithm in
     //       ProfileAutoCompleteResult.jsm and reuse it here.
-    const fieldOrder = [
+    let fieldOrder = [
       "name",
       "-moz-street-address-one-line",  // Street address
       "address-level2",  // City/Town
       "organization",    // Company or organization name
       "address-level1",  // Province/State (Standardized code if possible)
       "country-name",    // Country name
       "postal-code",     // Postal code
       "tel",             // Phone number
       "email",           // Email address
     ];
 
     address = {...address};
     let parts = [];
+    if (addressFields) {
+      let requiredFields = addressFields.trim().split(/\s+/);
+      fieldOrder = fieldOrder.filter(name => requiredFields.includes(name));
+    }
     if (address["street-address"]) {
       address["-moz-street-address-one-line"] = this.toOneLineAddress(
         address["street-address"]
       );
     }
     for (const fieldName of fieldOrder) {
       let string = address[fieldName];
       if (string) {
         parts.push(string);
       }
-      if (parts.length == 2) {
+      if (parts.length == 2 && !addressFields) {
         break;
       }
     }
     return parts.join(", ");
   },
 
   toOneLineAddress(address, delimiter = "\n") {
     let array = typeof address == "string" ? address.split(delimiter) : address;

--- a/build/autoconf/nspr-build.m4
+++ b/build/autoconf/nspr-build.m4
@@ -151,18 +151,18 @@ if test -n "$MOZ_SYSTEM_NSPR" -o -n "$NS
                 AC_MSG_ERROR([system NSPR does not support PR_STATIC_ASSERT or including prtypes.h does not provide it]))
     AC_TRY_COMPILE([#include "prtypes.h"],
                 [#ifndef PR_UINT64
                  #error PR_UINT64 not defined or requires including prtypes.h
                  #endif],
                 ,
                 AC_MSG_ERROR([system NSPR does not support PR_UINT64 or including prtypes.h does not provide it]))
     CFLAGS=$_SAVE_CFLAGS
-    NSPR_INCLUDE_DIR=`echo ${NSPR_CFLAGS} | sed -e 's/.*-I\([^ ]*\).*/\1/'`
-    NSPR_LIB_DIR=`echo ${NSPR_LIBS} | sed -e 's/.*-L\([^ ]*\).*/\1/'`
+    NSPR_INCLUDE_DIR=`echo ${NSPR_CFLAGS} | sed -e 's/.*-I\([[^ ]]*\).*/\1/'`
+    NSPR_LIB_DIR=`echo ${NSPR_LIBS} | sed -e 's/.*-L\([[^ ]]*\).*/\1/'`
 elif test -z "$JS_POSIX_NSPR"; then
     NSPR_INCLUDE_DIR="${DIST}/include/nspr"
     NSPR_CFLAGS="-I${NSPR_INCLUDE_DIR}"
     if test -n "$GNU_CC"; then
         if test -n "$MOZ_FOLD_LIBS"; then
            NSPR_LIB_DIR=${DIST}/lib
         else
            NSPR_LIB_DIR=${DIST}/bin

--- a/build/autoconf/sanitize.m4
+++ b/build/autoconf/sanitize.m4
@@ -1,34 +1,18 @@
 dnl This Source Code Form is subject to the terms of the Mozilla Public
 dnl License, v. 2.0. If a copy of the MPL was not distributed with this
 dnl file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 AC_DEFUN([MOZ_CONFIG_SANITIZE], [
 
 dnl ========================================================
-dnl = Link Time Optimization (LTO)
-dnl ========================================================
-if test -n "$MOZ_LTO"; then
-    MOZ_LLVM_HACKS=1
-    AC_DEFINE(MOZ_LTO)
-    MOZ_PATH_PROG(LLVM_SYMBOLIZER, llvm-symbolizer)
-
-    CFLAGS="$CFLAGS $MOZ_LTO_CFLAGS"
-    CPPFLAGS="$CPPFLAGS $MOZ_LTO_CFLAGS"
-    CXXFLAGS="$CXXFLAGS $MOZ_LTO_CFLAGS"
-    LDFLAGS="$LDFLAGS $MOZ_LTO_LDFLAGS"
-fi
-AC_SUBST(MOZ_LTO)
-
-dnl ========================================================
 dnl = Use Address Sanitizer
 dnl ========================================================
 if test -n "$MOZ_ASAN"; then
-    MOZ_LLVM_HACKS=1
     if test -n "$CLANG_CL"; then
         # Look for the ASan runtime binary
         if test "$CPU_ARCH" = "x86_64"; then
           MOZ_CLANG_RT_ASAN_LIB=clang_rt.asan_dynamic-x86_64.dll
         else
           MOZ_CLANG_RT_ASAN_LIB=clang_rt.asan_dynamic-i386.dll
         fi
         # We use MOZ_PATH_PROG in order to get a Windows style path.
@@ -56,17 +40,16 @@ AC_SUBST(MOZ_ASAN)
 dnl ========================================================
 dnl = Use Memory Sanitizer
 dnl ========================================================
 MOZ_ARG_ENABLE_BOOL(memory-sanitizer,
 [  --enable-memory-sanitizer       Enable Memory Sanitizer (default=no)],
     MOZ_MSAN=1,
     MOZ_MSAN= )
 if test -n "$MOZ_MSAN"; then
-    MOZ_LLVM_HACKS=1
     CFLAGS="-fsanitize=memory -fsanitize-memory-track-origins $CFLAGS"
     CXXFLAGS="-fsanitize=memory -fsanitize-memory-track-origins $CXXFLAGS"
     if test -z "$CLANG_CL"; then
         LDFLAGS="-fsanitize=memory -fsanitize-memory-track-origins $LDFLAGS"
     fi
     AC_DEFINE(MOZ_MSAN)
     MOZ_PATH_PROG(LLVM_SYMBOLIZER, llvm-symbolizer)
 fi
@@ -75,17 +58,16 @@ AC_SUBST(MOZ_MSAN)
 dnl ========================================================
 dnl = Use Thread Sanitizer
 dnl ========================================================
 MOZ_ARG_ENABLE_BOOL(thread-sanitizer,
 [  --enable-thread-sanitizer       Enable Thread Sanitizer (default=no)],
    MOZ_TSAN=1,
    MOZ_TSAN= )
 if test -n "$MOZ_TSAN"; then
-    MOZ_LLVM_HACKS=1
     CFLAGS="-fsanitize=thread $CFLAGS"
     CXXFLAGS="-fsanitize=thread $CXXFLAGS"
     if test -z "$CLANG_CL"; then
         LDFLAGS="-fsanitize=thread $LDFLAGS"
     fi
     AC_DEFINE(MOZ_TSAN)
     MOZ_PATH_PROG(LLVM_SYMBOLIZER, llvm-symbolizer)
 fi
@@ -100,17 +82,16 @@ MOZ_ARG_ENABLE_BOOL(signed-overflow-sani
    MOZ_SIGNED_OVERFLOW_SANITIZE=1,
    MOZ_SIGNED_OVERFLOW_SANITIZE= )
 MOZ_ARG_ENABLE_BOOL(unsigned-overflow-sanitizer,
 [  --enable-unsigned-overflow-sanitizer       Enable UndefinedBehavior Sanitizer (Unsigned Integer Overflow Parts, default=no)],
    MOZ_UNSIGNED_OVERFLOW_SANITIZE=1,
    MOZ_UNSIGNED_OVERFLOW_SANITIZE= )
 
 if test -n "$MOZ_SIGNED_OVERFLOW_SANITIZE$MOZ_UNSIGNED_OVERFLOW_SANITIZE"; then
-    MOZ_LLVM_HACKS=1
     MOZ_UBSAN=1
     SANITIZER_BLACKLISTS=""
     if test -n "$MOZ_SIGNED_OVERFLOW_SANITIZE"; then
         SANITIZER_BLACKLISTS="-fsanitize-blacklist=$_topsrcdir/build/sanitizers/ubsan_signed_overflow_blacklist.txt $SANITIZER_BLACKLISTS"
         CFLAGS="-fsanitize=signed-integer-overflow $CFLAGS"
         CXXFLAGS="-fsanitize=signed-integer-overflow $CXXFLAGS"
         if test -z "$CLANG_CL"; then
             LDFLAGS="-fsanitize=signed-integer-overflow $LDFLAGS"
@@ -134,28 +115,14 @@ fi
 AC_SUBST(MOZ_SIGNED_OVERFLOW_SANITIZE)
 AC_SUBST(MOZ_UNSIGNED_OVERFLOW_SANITIZE)
 AC_SUBST(MOZ_UBSAN)
 
 # The LLVM symbolizer is used by all sanitizers
 AC_SUBST(LLVM_SYMBOLIZER)
 
 dnl ========================================================
-dnl = Enable hacks required for LLVM instrumentations
-dnl ========================================================
-MOZ_ARG_ENABLE_BOOL(llvm-hacks,
-[  --enable-llvm-hacks       Enable workarounds required for several LLVM instrumentations (default=no)],
-    MOZ_LLVM_HACKS=1,
-    MOZ_LLVM_HACKS= )
-if test -n "$MOZ_LLVM_HACKS"; then
-    MOZ_NO_WLZDEFS=1
-    MOZ_CFLAGS_NSS=1
-fi
-AC_SUBST(MOZ_NO_WLZDEFS)
-AC_SUBST(MOZ_CFLAGS_NSS)
-
-dnl ========================================================
 dnl = Test for whether the compiler is compatible with the
 dnl = given sanitize options.
 dnl ========================================================
 AC_TRY_LINK(,,,AC_MSG_ERROR([compiler is incompatible with sanitize options]))
 
 ])

--- a/build/moz.configure/toolchain.configure
+++ b/build/moz.configure/toolchain.configure
@@ -928,29 +928,29 @@ def compiler(language, host_or_target, c
             raise FatalCheckError(
                 'Only clang/llvm 3.6 or newer is supported.')
 
         if info.type == 'msvc':
             if info.version < '19.13.26128':
                 raise FatalCheckError(
                     'This version (%s) of the MSVC compiler is not '
                     'supported.\n'
-                    'You must install Visual C++ 2017 Update 6 in '
-                    'order to build.\n'
+                    'You must install Visual C++ 2017 Update 6 or '
+                    'Update 8 or later in order to build.\n'
                     'See https://developer.mozilla.org/en/'
                     'Windows_Build_Prerequisites' % info.version)
 
             # MSVC version 15.7 and the previews for 15.8, at least,
             # can't build Firefox.
-            if info.version >= '19.14.0':
+            if info.version >= '19.14.0' and info.version < '19.15.0':
                 raise FatalCheckError(
                     'This version (%s) of the MSVC compiler is not '
                     'supported due to compiler bugs.\n'
-                    'You must install Visual C++ 2017 Update 6 in '
-                    'order to build.\n'
+                    'You must install Visual C++ 2017 Update 6 or '
+                    'Update 8 or later in order to build.\n'
                     'See https://developer.mozilla.org/en/'
                     'Windows_Build_Prerequisites' % info.version)
 
         if info.flags:
             raise FatalCheckError(
                 'Unknown compiler or compiler not supported.')
 
         return namespace(
@@ -1398,18 +1398,20 @@ def lto(value, pgo, c_compiler):
     return namespace(
         enabled=enabled,
         cflags=cflags,
         ldflags=ldflags
     )
 
 
 add_old_configure_assignment('MOZ_LTO', lto.enabled)
-add_old_configure_assignment('MOZ_LTO_CFLAGS', lto.cflags)
-add_old_configure_assignment('MOZ_LTO_LDFLAGS', lto.ldflags)
+set_config('MOZ_LTO', lto.enabled)
+set_define('MOZ_LTO', lto.enabled)
+set_config('MOZ_LTO_CFLAGS', lto.cflags)
+set_config('MOZ_LTO_LDFLAGS', lto.ldflags)
 
 # ASAN
 # ==============================================================
 
 js_option('--enable-address-sanitizer', help='Enable Address Sanitizer')
 
 
 @depends_if('--enable-address-sanitizer')

--- a/build/unix/elfhack/inject/moz.build
+++ b/build/unix/elfhack/inject/moz.build
@@ -33,12 +33,12 @@ for v in ('OS_CPPFLAGS', 'OS_CFLAGS', 'D
     for flag in COMPILE_FLAGS[v]:
         if flag == '-isystem':
             flags.append(''.join(COMPILE_FLAGS[v][idx:idx + 2]))
         elif flag.startswith(('-m', '-I', '-isystem')):
             flags.append(flag)
         idx += 1
     COMPILE_FLAGS[v] = flags
 
-COMPILE_FLAGS['OS_CFLAGS'] += ['-O2', '-fno-stack-protector']
+COMPILE_FLAGS['OS_CFLAGS'] += ['-O2', '-fno-stack-protector', '-fno-lto']
 
 AllowCompilerWarnings()
 NoVisibilityFlags()

--- a/build/unix/elfhack/moz.build
+++ b/build/unix/elfhack/moz.build
@@ -9,21 +9,19 @@ DIRS += ['inject']
 
 if not CONFIG['CROSS_COMPILE']:
     SOURCES += [
         'dummy.c',
         'test-array.c',
         'test-ctors.c',
     ]
 
-    for f in CONFIG['OS_CFLAGS']:
-        if f.startswith('-flto'):
-            SOURCES['dummy.c'].flags += ['-fno-lto']
-            SOURCES['test-array.c'].flags += ['-fno-lto']
-            SOURCES['test-ctors.c'].flags += ['-fno-lto']
+    SOURCES['dummy.c'].flags += ['-fno-lto']
+    SOURCES['test-array.c'].flags += ['-fno-lto']
+    SOURCES['test-ctors.c'].flags += ['-fno-lto']
 
 HOST_SOURCES += [
     'elf.cpp',
     'elfhack.cpp',
 ]
 
 HostProgram('elfhack')
 

--- a/build/unix/mozconfig.linux
+++ b/build/unix/mozconfig.linux
@@ -2,17 +2,17 @@ if [ "x$IS_NIGHTLY" = "xyes" ]; then
   # Some nightlies (eg: Mulet) don't want these set.
   MOZ_AUTOMATION_UPDATE_PACKAGING=${MOZ_AUTOMATION_UPDATE_PACKAGING-1}
 fi
 
 . "$topsrcdir/build/mozconfig.common"
 
 TOOLTOOL_DIR=${TOOLTOOL_DIR:-$topsrcdir}
 
-if [ -n "$FORCE_GCC" ]; then
+if [ -n "$FORCE_GCC" -o -n "$MOZ_PGO" ]; then
     CC="$TOOLTOOL_DIR/gcc/bin/gcc"
     CXX="$TOOLTOOL_DIR/gcc/bin/g++"
 else
     CC="$TOOLTOOL_DIR/clang/bin/clang"
     CXX="$TOOLTOOL_DIR/clang/bin/clang++"
 fi
 
 # We want to make sure we use binutils and other binaries in the tooltool

--- a/config/config.mk
+++ b/config/config.mk
@@ -194,22 +194,22 @@ INCLUDES = \
   -I$(srcdir) \
   -I$(CURDIR) \
   $(LOCAL_INCLUDES) \
   -I$(ABS_DIST)/include \
   $(NULL)
 
 include $(MOZILLA_DIR)/config/static-checking-config.mk
 
-LDFLAGS		= $(COMPUTED_LDFLAGS) $(PGO_LDFLAGS) $(MK_LDFLAGS)
+LDFLAGS		= $(MOZ_LTO_LDFLAGS) $(COMPUTED_LDFLAGS) $(PGO_LDFLAGS) $(MK_LDFLAGS)
 
-COMPILE_CFLAGS	= $(COMPUTED_CFLAGS) $(PGO_CFLAGS) $(_DEPEND_CFLAGS) $(MK_COMPILE_DEFINES)
-COMPILE_CXXFLAGS = $(COMPUTED_CXXFLAGS) $(PGO_CFLAGS) $(_DEPEND_CFLAGS) $(MK_COMPILE_DEFINES)
-COMPILE_CMFLAGS = $(OS_COMPILE_CMFLAGS) $(MOZBUILD_CMFLAGS)
-COMPILE_CMMFLAGS = $(OS_COMPILE_CMMFLAGS) $(MOZBUILD_CMMFLAGS)
+COMPILE_CFLAGS	= $(MOZ_LTO_CFLAGS) $(COMPUTED_CFLAGS) $(PGO_CFLAGS) $(_DEPEND_CFLAGS) $(MK_COMPILE_DEFINES)
+COMPILE_CXXFLAGS = $(MOZ_LTO_CFLAGS) $(COMPUTED_CXXFLAGS) $(PGO_CFLAGS) $(_DEPEND_CFLAGS) $(MK_COMPILE_DEFINES)
+COMPILE_CMFLAGS = $(MOZ_LTO_CFLAGS) $(OS_COMPILE_CMFLAGS) $(MOZBUILD_CMFLAGS)
+COMPILE_CMMFLAGS = $(MOZ_LTO_CFLAGS) $(OS_COMPILE_CMMFLAGS) $(MOZBUILD_CMMFLAGS)
 ASFLAGS = $(COMPUTED_ASFLAGS)
 SFLAGS = $(COMPUTED_SFLAGS)
 
 HOST_CFLAGS = $(COMPUTED_HOST_CFLAGS) $(_DEPEND_CFLAGS)
 HOST_CXXFLAGS = $(COMPUTED_HOST_CXXFLAGS) $(_DEPEND_CFLAGS)
 HOST_C_LDFLAGS = $(COMPUTED_HOST_C_LDFLAGS)
 HOST_CXX_LDFLAGS = $(COMPUTED_HOST_CXX_LDFLAGS)
 

--- a/config/rules.mk
+++ b/config/rules.mk
@@ -383,18 +383,27 @@ ifneq (,$(filter ml%,$(AS)))
 ASOUTOPTION = -Fo# eol
 else
 ASOUTOPTION = -o # eol
 endif
 
 ifeq (,$(CROSS_COMPILE))
 HOST_OUTOPTION = $(OUTOPTION)
 else
+# Windows-to-Windows cross compiles should always use MSVC-style options for
+# host compiles.
+ifeq (WINNT_WINNT,$(HOST_OS_ARCH)_$(OS_ARCH))
+ifneq (,$(filter-out msvc clang-cl,$(HOST_CC_TYPE)))
+$(error MSVC-style compilers should be used for host compilations!)
+endif
+HOST_OUTOPTION = -Fo# eol
+else
 HOST_OUTOPTION = -o # eol
 endif
+endif
 ################################################################################
 
 # Ensure the build config is up to date. This is done automatically when builds
 # are performed through |mach build|. The check here is to catch people not
 # using mach. If we ever enforce builds through mach, this code can be removed.
 ifndef MOZBUILD_BACKEND_CHECKED
 ifndef MACH
 ifndef TOPLEVEL_BUILD

--- a/config/tests/unit-nsinstall.py
+++ b/config/tests/unit-nsinstall.py
@@ -163,17 +163,17 @@ class TestNsinstall(unittest.TestCase):
             testdir = self.mkdirs(u"\u4241\u1D04\u1414")
             # We don't use subprocess because it can't handle Unicode on
             # Windows <http://bugs.python.org/issue1759845>. mozprocess calls
             # CreateProcessW directly so it's perfect.
             p = processhandler.ProcessHandlerMixin([sys.executable,
                                                     NSINSTALL_PATH,
                                                     testfile, testdir])
             p.run()
-            rv = p.waitForFinish()
+            rv = p.wait()
 
             self.assertEqual(rv, 0)
             destfile = os.path.join(testdir, filename)
             self.assert_(os.path.isfile(destfile))
 
     # TODO: implement -R, -l, -L and test them!
 
 

--- a/devtools/client/inspector/markup/test/browser_markup_events-windowed-host.js
+++ b/devtools/client/inspector/markup/test/browser_markup_events-windowed-host.js
@@ -46,18 +46,18 @@ async function runTests(inspector) {
   await onInspectorUpdated;
 
   ok(tooltip.isVisible(), "EventTooltip visible.");
 
   onInspectorUpdated = inspector.once("inspector-updated");
   const onTooltipHidden = tooltip.once("hidden");
 
   info("Click on another tag to hide the event tooltip");
-  const h1 = await getContainerForSelector("h1", inspector);
-  const tag = h1.elt.querySelector(".tag");
+  const script = await getContainerForSelector("script", inspector);
+  const tag = script.elt.querySelector(".tag");
   EventUtils.synthesizeMouseAtCenter(tag, {}, inspector.markup.doc.defaultView);
 
   await onTooltipHidden;
   // New node is selected, wait for inspector-updated.
   await onInspectorUpdated;
 
   ok(!tooltip.isVisible(), "EventTooltip hidden.");
 }

--- a/devtools/client/themes/markup.css
+++ b/devtools/client/themes/markup.css
@@ -389,29 +389,35 @@ ul.children + .tag-line::before {
 /* Applicable to the DOCTYPE */
 .doctype {
   font-style: italic;
 }
 
 /* Markup Badges */
 .markup-badge {
   display: inline-block;
-  font-size: 9px;
+  font-size: 10px;
   font-weight: normal;
   line-height: 11px;
   vertical-align: 1px;
   border: 1px solid var(--markup-badge-border-color);
   border-radius: 3px;
   padding: 0px 2px;
   margin-inline-start: 5px;
   -moz-user-select: none;
   background-color: var(--markup-badge-background-color);
   color: var(--markup-badge-color);
 }
 
+@media (min-resolution: 1.1dppx) {
+  .markup-badge {
+    font-size: 9px;
+  }
+}
+
 .markup-badge.active {
   background-color: var(--markup-badge-active-background-color);
   border-color: var(--theme-selection-color);
   color: var(--theme-selection-color);
 }
 
 .markup-badge[data-custom],
 .markup-badge[data-display="flex"].interactive,

--- a/devtools/shared/heapsnapshot/tests/gtest/DeserializedStackFrameUbiStackFrames.cpp
+++ b/devtools/shared/heapsnapshot/tests/gtest/DeserializedStackFrameUbiStackFrames.cpp
@@ -3,16 +3,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 // Test that the `JS::ubi::StackFrame`s we create from
 // `mozilla::devtools::DeserializedStackFrame` instances look and behave as we would
 // like.
 
 #include "DevTools.h"
+#include "js/SavedFrameAPI.h"
 #include "js/TypeDecls.h"
 #include "mozilla/devtools/DeserializedNode.h"
 
 using testing::Field;
 using testing::ReturnRef;
 
 // A mock DeserializedStackFrame for testing.
 struct MockDeserializedStackFrame : public DeserializedStackFrame

--- a/dom/base/BodyUtil.cpp
+++ b/dom/base/BodyUtil.cpp
@@ -13,16 +13,17 @@
 
 #include "nsCharSeparatedTokenizer.h"
 #include "nsDOMString.h"
 #include "nsNetUtil.h"
 #include "nsReadableUtils.h"
 #include "nsStreamUtils.h"
 #include "nsStringStream.h"
 
+#include "js/JSON.h"
 #include "mozilla/ErrorResult.h"
 #include "mozilla/dom/Exceptions.h"
 #include "mozilla/dom/FetchUtil.h"
 #include "mozilla/dom/File.h"
 #include "mozilla/dom/FormData.h"
 #include "mozilla/dom/Headers.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/URLSearchParams.h"

--- a/dom/base/ChromeUtils.cpp
+++ b/dom/base/ChromeUtils.cpp
@@ -1,16 +1,18 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "ChromeUtils.h"
 
+#include "js/AutoByteString.h"
+#include "js/SavedFrameAPI.h"
 #include "jsfriendapi.h"
 #include "WrapperFactory.h"
 
 #include "mozilla/Base64.h"
 #include "mozilla/BasePrincipal.h"
 #include "mozilla/CycleCollectedJSRuntime.h"
 #include "mozilla/PerformanceMetricsCollector.h"
 #include "mozilla/Preferences.h"

new file mode 100644
--- /dev/null
+++ b/dom/base/VisualViewport.cpp
@@ -0,0 +1,140 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VisualViewport.h"
+#include "nsIScrollableFrame.h"
+#include "nsIDocShell.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+VisualViewport::VisualViewport(nsPIDOMWindowInner* aWindow)
+  : DOMEventTargetHelper(aWindow)
+{
+}
+
+VisualViewport::~VisualViewport()
+{
+}
+
+/* virtual */
+JSObject*
+VisualViewport::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+  return VisualViewport_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+CSSSize
+VisualViewport::VisualViewportSize() const
+{
+  CSSSize size = CSSSize(0,0);
+
+  nsIPresShell* presShell = GetPresShell();
+  if (presShell) {
+    if (presShell->IsVisualViewportSizeSet()) {
+      size = CSSRect::FromAppUnits(
+        presShell->GetVisualViewportSize());
+    } else {
+      nsIScrollableFrame* sf = presShell->GetRootScrollFrameAsScrollable();
+      if (sf) {
+        size = CSSRect::FromAppUnits(sf->GetScrollPortRect().Size());
+      }
+    }
+  }
+  return size;
+}
+
+double
+VisualViewport::Width() const
+{
+  CSSSize size = VisualViewportSize();
+  return size.width;
+}
+
+double
+VisualViewport::Height() const
+{
+  CSSSize size = VisualViewportSize();
+  return size.height;
+}
+
+double
+VisualViewport::Scale() const
+{
+  double scale = 1;
+  nsIPresShell* presShell = GetPresShell();
+  if (presShell) {
+    scale = presShell->GetResolution();
+  }
+  return scale;
+}
+
+CSSPoint
+VisualViewport::VisualViewportOffset() const
+{
+  CSSPoint offset = CSSPoint(0,0);
+
+  nsIPresShell* presShell = GetPresShell();
+  if (presShell) {
+      offset = CSSPoint::FromAppUnits(presShell->GetVisualViewportOffset());
+  }
+  return offset;
+}
+
+CSSPoint
+VisualViewport::LayoutViewportOffset() const
+{
+  CSSPoint offset = CSSPoint(0,0);
+
+  nsIPresShell* presShell = GetPresShell();
+  if (presShell) {
+    nsIScrollableFrame* sf = presShell->GetRootScrollFrameAsScrollable();
+    if (sf) {
+      offset = CSSPoint::FromAppUnits(sf->GetScrollPosition());
+    }
+  }
+  return offset;
+}
+
+double
+VisualViewport::PageLeft() const
+{
+  return VisualViewportOffset().X();
+}
+
+double
+VisualViewport::PageTop() const
+{
+  return VisualViewportOffset().Y();
+}
+
+double
+VisualViewport::OffsetLeft() const
+{
+  return PageLeft() - LayoutViewportOffset().X();
+}
+
+double
+VisualViewport::OffsetTop() const
+{
+  return PageTop() - LayoutViewportOffset().Y();
+}
+
+nsIPresShell*
+VisualViewport::GetPresShell() const
+{
+  nsCOMPtr<nsPIDOMWindowInner> window = GetOwner();
+  if (!window) {
+    return nullptr;
+  }
+
+  nsIDocShell* docShell = window->GetDocShell();
+  if (!docShell) {
+    return nullptr;
+  }
+
+  return docShell->GetPresShell();
+}

new file mode 100644
--- /dev/null
+++ b/dom/base/VisualViewport.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+#ifndef mozilla_dom_VisualViewport_h
+#define mozilla_dom_VisualViewport_h
+
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/dom/VisualViewportBinding.h"
+#include "Units.h"
+#include "nsIPresShell.h"
+
+namespace mozilla {
+namespace dom {
+
+/* Visual Viewport API spec:  https://wicg.github.io/visual-viewport/#the-visualviewport-interface */
+class VisualViewport final: public mozilla::DOMEventTargetHelper
+{
+
+public:
+  explicit VisualViewport(nsPIDOMWindowInner* aWindow);
+
+  double OffsetLeft() const;
+  double OffsetTop() const;
+  double PageLeft() const;
+  double PageTop() const;
+  double Width() const;
+  double Height() const;
+  double Scale() const;
+
+  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+
+private:
+  virtual ~VisualViewport();
+
+  CSSSize VisualViewportSize() const;
+  CSSPoint VisualViewportOffset() const;
+  CSSPoint LayoutViewportOffset() const;
+  nsIPresShell* GetPresShell() const;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_VisualViewport_h

--- a/dom/base/moz.build
+++ b/dom/base/moz.build
@@ -222,16 +222,17 @@ EXPORTS.mozilla.dom += [
     'SyncMessageSender.h',
     'TabGroup.h',
     'Text.h',
     'Timeout.h',
     'TimeoutHandler.h',
     'TimeoutManager.h',
     'TreeIterator.h',
     'TreeWalker.h',
+    'VisualViewport.h',
     'WebKitCSSMatrix.h',
     'WindowOrientationObserver.h',
 ]
 
 if CONFIG['FUZZING']:
     EXPORTS.mozilla.dom += [
         'FuzzingFunctions.h',
     ]
@@ -378,16 +379,17 @@ UNIFIED_SOURCES += [
     'TextInputProcessor.cpp',
     'ThirdPartyUtil.cpp',
     'Timeout.cpp',
     'TimeoutBudgetManager.cpp',
     'TimeoutExecutor.cpp',
     'TimeoutHandler.cpp',
     'TimeoutManager.cpp',
     'TreeWalker.cpp',
+    'VisualViewport.cpp',
     'WebKitCSSMatrix.cpp',
     'WindowDestroyedEvent.cpp',
     'WindowNamedPropertiesHandler.cpp',
     'WindowOrientationObserver.cpp',
     'XPathGenerator.cpp',
 ]
 
 if CONFIG['MOZ_WEBRTC']:

--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -15,16 +15,17 @@
 #include "harfbuzz/hb.h"
 #include "imgICache.h"
 #include "imgIContainer.h"
 #include "imgINotificationObserver.h"
 #include "imgLoader.h"
 #include "imgRequestProxy.h"
 #include "jsapi.h"
 #include "jsfriendapi.h"
+#include "js/JSON.h"
 #include "js/Value.h"
 #include "Layers.h"
 #include "nsAppRunner.h"
 // nsNPAPIPluginInstance must be included before nsIDocument.h, which is included in mozAutoDocUpdate.h.
 #include "nsNPAPIPluginInstance.h"
 #include "gfxDrawable.h"
 #include "gfxPrefs.h"
 #include "ImageOps.h"

--- a/dom/base/nsFrameMessageManager.cpp
+++ b/dom/base/nsFrameMessageManager.cpp
@@ -24,16 +24,17 @@
 #include "nsIInputStream.h"
 #include "nsIXULRuntime.h"
 #include "nsIScriptError.h"
 #include "nsIConsoleService.h"
 #include "nsIMemoryReporter.h"
 #include "nsIProtocolHandler.h"
 #include "nsIScriptSecurityManager.h"
 #include "xpcpublic.h"
+#include "js/JSON.h"
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/CycleCollectedJSContext.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/ScriptPreloader.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/dom/ChildProcessMessageManager.h"
 #include "mozilla/dom/ChromeMessageBroadcaster.h"
 #include "mozilla/dom/File.h"

--- a/dom/base/nsGlobalWindowInner.cpp
+++ b/dom/base/nsGlobalWindowInner.cpp
@@ -28,16 +28,17 @@
 #include "mozilla/dom/Performance.h"
 #include "mozilla/dom/StorageEvent.h"
 #include "mozilla/dom/StorageEventBinding.h"
 #include "mozilla/dom/StorageNotifierService.h"
 #include "mozilla/dom/StorageUtils.h"
 #include "mozilla/dom/Timeout.h"
 #include "mozilla/dom/TimeoutHandler.h"
 #include "mozilla/dom/TimeoutManager.h"
+#include "mozilla/dom/VisualViewport.h"
 #include "mozilla/IntegerPrintfMacros.h"
 #if defined(MOZ_WIDGET_ANDROID)
 #include "mozilla/dom/WindowOrientationObserver.h"
 #endif
 #include "nsDOMOfflineResourceList.h"
 #include "nsError.h"
 #include "nsIIdleService.h"
 #include "nsISizeOfEventTarget.h"
@@ -2212,16 +2213,25 @@ nsPIDOMWindowInner::Navigator()
 {
   if (!mNavigator) {
     mNavigator = new mozilla::dom::Navigator(this);
   }
 
   return mNavigator;
 }
 
+VisualViewport* nsGlobalWindowInner::VisualViewport()
+{
+  if (!mVisualViewport) {
+    mVisualViewport = new mozilla::dom::VisualViewport(this);
+  }
+
+  return mVisualViewport;
+}
+
 nsScreen*
 nsGlobalWindowInner::GetScreen(ErrorResult& aError)
 {
   if (!mScreen) {
     mScreen = nsScreen::Create(this);
     if (!mScreen) {
       aError.Throw(NS_ERROR_UNEXPECTED);
       return nullptr;

--- a/dom/base/nsGlobalWindowInner.h
+++ b/dom/base/nsGlobalWindowInner.h
@@ -121,16 +121,17 @@ class Promise;
 class PostMessageEvent;
 struct RequestInit;
 class RequestOrUSVString;
 class Selection;
 class SpeechSynthesis;
 class TabGroup;
 class Timeout;
 class U2F;
+class VisualViewport;
 class VRDisplay;
 enum class VRDisplayEventReason : uint8_t;
 class VREventObserver;
 class WakeLock;
 #if defined(MOZ_WIDGET_ANDROID)
 class WindowOrientationObserver;
 #endif
 class Worklet;
@@ -759,16 +760,17 @@ public:
   mozilla::dom::Storage* GetSessionStorage(mozilla::ErrorResult& aError);
   mozilla::dom::Storage*
   GetLocalStorage(mozilla::ErrorResult& aError);
   mozilla::dom::Selection* GetSelection(mozilla::ErrorResult& aError);
   mozilla::dom::IDBFactory* GetIndexedDB(mozilla::ErrorResult& aError);
   already_AddRefed<nsICSSDeclaration>
     GetComputedStyle(mozilla::dom::Element& aElt, const nsAString& aPseudoElt,
                      mozilla::ErrorResult& aError) override;
+  mozilla::dom::VisualViewport* VisualViewport();
   already_AddRefed<mozilla::dom::MediaQueryList> MatchMedia(
     const nsAString& aQuery,
     mozilla::dom::CallerType aCallerType,
     mozilla::ErrorResult& aError);
   nsScreen* GetScreen(mozilla::ErrorResult& aError);
   void MoveTo(int32_t aXPos, int32_t aYPos,
               mozilla::dom::CallerType aCallerType,
               mozilla::ErrorResult& aError);
@@ -1388,16 +1390,18 @@ protected:
   RefPtr<mozilla::dom::Storage> mLocalStorage;
   RefPtr<mozilla::dom::Storage> mSessionStorage;
 
   RefPtr<mozilla::EventListenerManager> mListenerManager;
   RefPtr<mozilla::dom::Location> mLocation;
   RefPtr<nsHistory>           mHistory;
   RefPtr<mozilla::dom::CustomElementRegistry> mCustomElements;
 
+  RefPtr<mozilla::dom::VisualViewport> mVisualViewport;
+
   nsCOMPtr<nsIPrincipal> mDocumentPrincipal;
   // mTabChild is only ever populated in the content process.
   nsCOMPtr<nsITabChild>  mTabChild;
 
   uint32_t mSuspendDepth;
   uint32_t mFreezeDepth;
 
   // the method that was used to focus mFocusedNode

--- a/dom/base/nsINode.cpp
+++ b/dom/base/nsINode.cpp
@@ -7,16 +7,17 @@
 /*
  * Base class for all DOM nodes.
  */
 
 #include "nsINode.h"
 
 #include "AccessCheck.h"
 #include "jsapi.h"
+#include "js/JSON.h"
 #include "mozAutoDocUpdate.h"
 #include "mozilla/AsyncEventDispatcher.h"
 #include "mozilla/CORSMode.h"
 #include "mozilla/EventDispatcher.h"
 #include "mozilla/EventListenerManager.h"
 #include "mozilla/HTMLEditor.h"
 #include "mozilla/InternalMutationEvent.h"
 #include "mozilla/Likely.h"

--- a/dom/base/nsJSUtils.h
+++ b/dom/base/nsJSUtils.h
@@ -14,17 +14,19 @@
  * the generated code itself.
  */
 
 #include "mozilla/Assertions.h"
 
 #include "GeckoProfiler.h"
 #include "jsapi.h"
 #include "jsfriendapi.h"
+#include "js/AutoByteString.h"
 #include "js/Conversions.h"
+#include "js/StableStringChars.h"
 #include "nsString.h"
 
 class nsIScriptContext;
 class nsIScriptElement;
 class nsIScriptGlobalObject;
 class nsXBLPrototypeBinding;
 
 namespace mozilla {
@@ -220,17 +222,17 @@ public:
 
   static void ResetTimeZone();
 };
 
 template<typename T>
 inline bool
 AssignJSString(JSContext *cx, T &dest, JSString *s)
 {
-  size_t len = js::GetStringLength(s);
+  size_t len = JS::GetStringLength(s);
   static_assert(js::MaxStringLength < (1 << 28),
                 "Shouldn't overflow here or in SetCapacity");
   if (MOZ_UNLIKELY(!dest.SetLength(len, mozilla::fallible))) {
     JS_ReportOutOfMemory(cx);
     return false;
   }
   return js::CopyStringChars(cx, dest.BeginWriting(), s, len);
 }

--- a/dom/bindings/BindingUtils.cpp
+++ b/dom/bindings/BindingUtils.cpp
@@ -12,16 +12,18 @@
 #include "mozilla/Assertions.h"
 #include "mozilla/DebugOnly.h"
 #include "mozilla/FloatingPoint.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Unused.h"
 #include "mozilla/UseCounter.h"
 
 #include "AccessCheck.h"
+#include "js/JSON.h"
+#include "js/StableStringChars.h"
 #include "jsfriendapi.h"
 #include "nsContentCreatorFunctions.h"
 #include "nsContentUtils.h"
 #include "nsGlobalWindow.h"
 #include "nsHTMLTags.h"
 #include "nsIDocShell.h"
 #include "nsIDOMGlobalPropertyInitializer.h"
 #include "nsINode.h"
@@ -2853,17 +2855,17 @@ ConvertJSValueToByteString(JSContext* cx
       // terminator.
       char badCharArray[6];
       static_assert(sizeof(char16_t) <= 2, "badCharArray too small");
       SprintfLiteral(badCharArray, "%d", badChar);
       ThrowErrorMessage(cx, MSG_INVALID_BYTESTRING, index, badCharArray);
       return false;
     }
   } else {
-    length = js::GetStringLength(s);
+    length = JS::GetStringLength(s);
   }
 
   static_assert(js::MaxStringLength < UINT32_MAX,
                 "length+1 shouldn't overflow");
 
   if (!result.SetLength(length, fallible)) {
     return false;
   }

--- a/dom/bindings/BindingUtils.h
+++ b/dom/bindings/BindingUtils.h
@@ -3,16 +3,17 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_dom_BindingUtils_h__
 #define mozilla_dom_BindingUtils_h__
 
 #include "jsfriendapi.h"
+#include "js/AutoByteString.h"
 #include "js/Wrapper.h"
 #include "js/Conversions.h"
 #include "mozilla/ArrayUtils.h"
 #include "mozilla/Alignment.h"
 #include "mozilla/Array.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/DeferredFinalize.h"
 #include "mozilla/dom/BindingDeclarations.h"

--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -1059,16 +1059,20 @@ DOMInterfaces = {
 'TreeContentView': {
     'nativeType': 'nsTreeContentView',
 },
 
 'TreeWalker': {
     'wrapperCache': False,
 },
 
+'VisualViewport': {
+    'nativeType': 'mozilla::dom::VisualViewport',
+},
+
 'VTTCue': {
     'nativeType': 'mozilla::dom::TextTrackCue'
 },
 
 'VTTRegion': {
   'nativeType': 'mozilla::dom::TextTrackRegion',
 },
 

--- a/dom/bindings/DOMJSClass.h
+++ b/dom/bindings/DOMJSClass.h
@@ -2,16 +2,17 @@
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_dom_DOMJSClass_h
 #define mozilla_dom_DOMJSClass_h
 
+#include "jsapi.h"
 #include "jsfriendapi.h"
 #include "js/Wrapper.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/Likely.h"
 
 #include "mozilla/dom/PrototypeList.h" // auto-generated
 

--- a/dom/bindings/Exceptions.cpp
+++ b/dom/bindings/Exceptions.cpp
@@ -4,16 +4,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "mozilla/dom/Exceptions.h"
 
 #include "js/RootingAPI.h"
 #include "js/TypeDecls.h"
 #include "jsapi.h"
+#include "js/SavedFrameAPI.h"
 #include "mozilla/CycleCollectedJSContext.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/DOMException.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "nsPIDOMWindow.h"
 #include "nsServiceManagerUtils.h"
 #include "nsThreadUtils.h"
 #include "XPCWrapper.h"

--- a/dom/console/ConsoleAPIStorage.js
+++ b/dom/console/ConsoleAPIStorage.js
@@ -41,22 +41,16 @@ const CONSOLEAPISTORAGE_CID = Components
 function ConsoleAPIStorageService() {
   this.init();
 }
 
 ConsoleAPIStorageService.prototype = {
   classID : CONSOLEAPISTORAGE_CID,
   QueryInterface: ChromeUtils.generateQI([Ci.nsIConsoleAPIStorage,
                                           Ci.nsIObserver]),
-  classInfo: XPCOMUtils.generateCI({
-    classID: CONSOLEAPISTORAGE_CID,
-    contractID: '@mozilla.org/consoleAPI-storage;1',
-    interfaces: [Ci.nsIConsoleAPIStorage, Ci.nsIObserver],
-    flags: Ci.nsIClassInfo.SINGLETON
-  }),
 
   observe: function CS_observe(aSubject, aTopic, aData)
   {
     if (aTopic == "xpcom-shutdown") {
       Services.obs.removeObserver(this, "xpcom-shutdown");
       Services.obs.removeObserver(this, "inner-window-destroyed");
       Services.obs.removeObserver(this, "memory-pressure");
     }

--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -10,16 +10,17 @@
 
 #include "gfxPrefs.h"
 #ifdef ACCESSIBILITY
 #include "mozilla/a11y/DocAccessibleChild.h"
 #endif
 #include "Layers.h"
 #include "ContentChild.h"
 #include "TabParent.h"
+#include "js/JSON.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/BrowserElementParent.h"
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/EventListenerManager.h"
 #include "mozilla/dom/DataTransfer.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/indexedDB/PIndexedDBPermissionRequestChild.h"
 #include "mozilla/dom/MessageManagerBinding.h"

--- a/dom/media/webvtt/WebVTTParserWrapper.js
+++ b/dom/media/webvtt/WebVTTParserWrapper.js
@@ -1,17 +1,16 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 ChromeUtils.import("resource://gre/modules/XPCOMUtils.jsm");
 ChromeUtils.import("resource://gre/modules/vtt.jsm");
 
 var WEBVTTPARSERWRAPPER_CID = "{acf6e493-0092-4b26-b172-241e375c57ab}";
-var WEBVTTPARSERWRAPPER_CONTRACTID = "@mozilla.org/webvttParserWrapper;1";
 
 function WebVTTParserWrapper()
 {
   // Nothing
 }
 
 WebVTTParserWrapper.prototype =
 {
@@ -55,16 +54,11 @@ WebVTTParserWrapper.prototype =
   processCues: function(window, cues, overlay, controls)
   {
     WebVTT.processCues(window, cues, overlay, controls);
   },
 
   classDescription: "Wrapper for the JS WebVTT implementation (vtt.js)",
   classID: Components.ID(WEBVTTPARSERWRAPPER_CID),
   QueryInterface: ChromeUtils.generateQI([Ci.nsIWebVTTParserWrapper]),
-  classInfo: XPCOMUtils.generateCI({
-    classID:    WEBVTTPARSERWRAPPER_CID,
-    contractID: WEBVTTPARSERWRAPPER_CONTRACTID,
-    interfaces: [Ci.nsIWebVTTParserWrapper]
-  })
 };
 
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([WebVTTParserWrapper]);

--- a/dom/payments/PaymentRequestUtils.cpp
+++ b/dom/payments/PaymentRequestUtils.cpp
@@ -1,14 +1,15 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "js/JSON.h"
 #include "nsArrayUtils.h"
 #include "PaymentRequestUtils.h"
 #include "nsIMutableArray.h"
 #include "nsISupportsPrimitives.h"
 
 namespace mozilla {
 namespace dom {
 

--- a/dom/plugins/base/nsJSNPRuntime.cpp
+++ b/dom/plugins/base/nsJSNPRuntime.cpp
@@ -1130,17 +1130,17 @@ nsJSObjWrapper::GetNewOrUsed(NPP npp, JS
 
   if (!sJSObjWrappers) {
     // No hash yet (or any more), initialize it.
     if (!CreateJSObjWrapperTable())
       return nullptr;
   }
   MOZ_ASSERT(sJSObjWrappersAccessible);
 
-  JSObjWrapperTable::Ptr p = sJSObjWrappers->lookupForAdd(nsJSObjWrapperKey(obj, npp));
+  JSObjWrapperTable::Ptr p = sJSObjWrappers->lookup(nsJSObjWrapperKey(obj, npp));
   if (p) {
     MOZ_ASSERT(p->value());
     // Found a live nsJSObjWrapper, return it.
 
     return _retainobject(p->value());
   }
 
   // No existing nsJSObjWrapper, create one.

--- a/dom/script/ScriptSettings.cpp
+++ b/dom/script/ScriptSettings.cpp
@@ -6,16 +6,17 @@
 
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/ThreadLocal.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/CycleCollectedJSContext.h"
 #include "mozilla/dom/WorkerPrivate.h"
 
 #include "jsapi.h"
+#include "js/StableStringChars.h"
 #include "xpcpublic.h"
 #include "nsIGlobalObject.h"
 #include "nsIDocShell.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsIScriptContext.h"
 #include "nsContentUtils.h"
 #include "nsGlobalWindow.h"
 #include "nsPIDOMWindow.h"
@@ -705,17 +706,17 @@ AutoEntryScript::DocshellEntryMonitor::E
       !window->GetDocShell()->GetRecordProfileTimelineMarkers()) {
     return;
   }
 
   nsCOMPtr<nsIDocShell> docShellForJSRunToCompletion = window->GetDocShell();
   nsString filename;
   uint32_t lineNumber = 0;
 
-  js::AutoStableStringChars functionName(aCx);
+  JS::AutoStableStringChars functionName(aCx);
   if (rootedFunction) {
     JS::Rooted<JSString*> displayId(aCx, JS_GetFunctionDisplayId(rootedFunction));
     if (displayId) {
       if (!functionName.initTwoByte(aCx, displayId)) {
         JS_ClearPendingException(aCx);
         return;
       }
     }

--- a/dom/tests/browser/browser_ConsoleAPITests.js
+++ b/dom/tests/browser/browser_ConsoleAPITests.js
@@ -47,17 +47,17 @@ function spawnWithObserver(browser, obse
     // before exiting the test
     "  let resolve = () => {",
     "    Services.obs.removeObserver(ConsoleObserver, 'console-api-log-event');",
     "    _resolve();",
     "  };",
     // This is the observer itself, it calls the passed-in function whenever
     // it encounters an event
     "  let ConsoleObserver = {",
-    "    QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),",
+    "    QueryInterface: ChromeUtils.generateQI([Ci.nsIObserver]),",
     "    observe: function(aSubject, aTopic, aData) {",
     "      try {",
     "        (" + observerFunc.toString() + ")(aSubject.wrappedJSObject);",
     "      } catch (ex) {",
     "        ok(false, 'Exception thrown in observe: ' + ex);",
     "      }",
     "    }",
     "  };",

--- a/dom/tests/mochitest/general/test_interfaces.js
+++ b/dom/tests/mochitest/general/test_interfaces.js
@@ -1157,16 +1157,18 @@ var interfaceNamesInGlobalScope =
     {name: "UserProximityEvent", insecureContext: true, disabled: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "ValidityState", insecureContext: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "VideoPlaybackQuality", insecureContext: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "VideoStreamTrack", insecureContext: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
+    {name: "VisualViewport", insecureContext: true},
+// IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "VRDisplay", insecureContext: true, releaseNonWindows: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "VRDisplayCapabilities", insecureContext: true, releaseNonWindows: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "VRDisplayEvent", insecureContext: true, releaseNonWindows: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "VREyeParameters", insecureContext: true, releaseNonWindows: false},
 // IMPORTANT: Do not change this list without review from a DOM peer!

new file mode 100644
--- /dev/null
+++ b/dom/webidl/VisualViewport.webidl
@@ -0,0 +1,21 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * The origin of this IDL file is:
+ * https://wicg.github.io/visual-viewport/#the-visualviewport-interface
+ */
+
+interface VisualViewport : EventTarget {
+  readonly attribute double offsetLeft;
+  readonly attribute double offsetTop;
+
+  readonly attribute double pageLeft;
+  readonly attribute double pageTop;
+
+  readonly attribute double width;
+  readonly attribute double height;
+
+  readonly attribute double scale;
+};

--- a/dom/webidl/Window.webidl
+++ b/dom/webidl/Window.webidl
@@ -11,16 +11,17 @@
  * http://dev.w3.org/csswg/cssom-view/
  * https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/RequestAnimationFrame/Overview.html
  * https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/NavigationTiming/Overview.html
  * https://dvcs.w3.org/hg/webcrypto-api/raw-file/tip/spec/Overview.html
  * http://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html
  * https://w3c.github.io/webappsec-secure-contexts/#monkey-patching-global-object
  * https://w3c.github.io/requestidlecallback/
  * https://drafts.css-houdini.org/css-paint-api-1/#dom-window-paintworklet
+ * https://wicg.github.io/visual-viewport/#the-visualviewport-interface
  */
 
 interface IID;
 interface nsIBrowserDOMWindow;
 interface XULControllers;
 interface nsIDOMWindowUtils;
 
 typedef OfflineResourceList ApplicationCache;
@@ -560,8 +561,14 @@ partial interface Window {
    * Getter funcion for IntlUtils, which provides helper functions for
    * localization.
    */
   [Throws, Func="IsChromeOrXBL"]
   readonly attribute IntlUtils intlUtils;
 };
 
 Window implements WebGPUProvider;
+
+partial interface Window {
+  [SameObject, Pref="dom.visualviewport.enabled", Replaceable]
+  readonly attribute VisualViewport visualViewport;
+
+};

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -913,16 +913,17 @@ WEBIDL_FILES = [
     'UIEvent.webidl',
     'URL.webidl',
     'URLSearchParams.webidl',
     'ValidityState.webidl',
     'VideoPlaybackQuality.webidl',
     'VideoStreamTrack.webidl',
     'VideoTrack.webidl',
     'VideoTrackList.webidl',
+    'VisualViewport.webidl',
     'VRDisplay.webidl',
     'VRDisplayEvent.webidl',
     'VRServiceTest.webidl',
     'VTTCue.webidl',
     'VTTRegion.webidl',
     'WaveShaperNode.webidl',
     'WebAuthentication.webidl',
     'WebComponents.webidl',

--- a/dom/xhr/XMLHttpRequestMainThread.cpp
+++ b/dom/xhr/XMLHttpRequestMainThread.cpp
@@ -69,16 +69,17 @@
 #include "nsIPromptFactory.h"
 #include "nsIWindowWatcher.h"
 #include "nsIConsoleService.h"
 #include "nsIContentSecurityPolicy.h"
 #include "nsAsyncRedirectVerifyHelper.h"
 #include "nsStringBuffer.h"
 #include "nsIFileChannel.h"
 #include "mozilla/Telemetry.h"
+#include "js/JSON.h"
 #include "jsfriendapi.h"
 #include "GeckoProfiler.h"
 #include "mozilla/dom/XMLHttpRequestBinding.h"
 #include "mozilla/Attributes.h"
 #include "MultipartBlobImpl.h"
 #include "nsIPermissionManager.h"
 #include "nsMimeTypes.h"
 #include "nsIHttpChannelInternal.h"

--- a/gfx/ipc/GPUChild.cpp
+++ b/gfx/ipc/GPUChild.cpp
@@ -3,16 +3,17 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "GPUChild.h"
 #include "gfxConfig.h"
 #include "gfxPrefs.h"
 #include "GPUProcessHost.h"
 #include "GPUProcessManager.h"
+#include "VRProcessManager.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/TelemetryIPC.h"
 #include "mozilla/dom/CheckerboardReportService.h"
 #include "mozilla/dom/MemoryReportRequest.h"
 #include "mozilla/gfx/gfxVars.h"
 #if defined(XP_WIN)
 # include "mozilla/gfx/DeviceManagerDx.h"
 #endif
@@ -105,16 +106,22 @@ GPUChild::EnsureGPUReady()
   }
 
   gfxPlatform::GetPlatform()->ImportGPUDeviceData(data);
   Telemetry::AccumulateTimeDelta(Telemetry::GPU_PROCESS_LAUNCH_TIME_MS_2, mHost->GetLaunchTime());
   mGPUReady = true;
   return true;
 }
 
+base::ProcessHandle
+GPUChild::GetChildProcessHandle()
+{
+  return mHost->GetChildProcessHandle();
+}
+
 PAPZInputBridgeChild*
 GPUChild::AllocPAPZInputBridgeChild(const LayersId& aLayersId)
 {
   APZInputBridgeChild* child = new APZInputBridgeChild();
   child->AddRef();
   return child;
 }
 
@@ -166,16 +173,34 @@ GPUChild::RecvInitCrashReporter(Shmem&& 
     GeckoProcessType_GPU,
     aShmem,
     aThreadId);
 
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
+GPUChild::RecvCreateVRProcess()
+{
+  // Make sure create VR process at the main process
+  MOZ_ASSERT(XRE_IsParentProcess());
+  if (gfxPrefs::VRProcessEnabled()) {
+    VRProcessManager::Initialize();
+    VRProcessManager* vr = VRProcessManager::Get();
+    MOZ_ASSERT(vr, "VRProcessManager must be initialized first.");
+
+    if (vr) {
+      vr->LaunchVRProcess();
+    }
+  }
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
 GPUChild::RecvNotifyUiObservers(const nsCString& aTopic)
 {
   nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
   MOZ_ASSERT(obsSvc);
   if (obsSvc) {
     obsSvc->NotifyObservers(nullptr, aTopic.get(), nullptr);
   }
   return IPC_OK();

--- a/gfx/ipc/GPUChild.h
+++ b/gfx/ipc/GPUChild.h
@@ -31,27 +31,29 @@ class GPUChild final
 
 public:
   explicit GPUChild(GPUProcessHost* aHost);
   ~GPUChild();
 
   void Init();
 
   bool EnsureGPUReady();
+  base::ProcessHandle GetChildProcessHandle();
 
   PAPZInputBridgeChild* AllocPAPZInputBridgeChild(const LayersId& aLayersId) override;
   bool DeallocPAPZInputBridgeChild(PAPZInputBridgeChild* aActor) override;
 
   // gfxVarReceiver overrides.
   void OnVarChanged(const GfxVarUpdate& aVar) override;
 
   // PGPUChild overrides.
   mozilla::ipc::IPCResult RecvInitComplete(const GPUDeviceData& aData) override;
   mozilla::ipc::IPCResult RecvReportCheckerboard(const uint32_t& aSeverity, const nsCString& aLog) override;
   mozilla::ipc::IPCResult RecvInitCrashReporter(Shmem&& shmem, const NativeThreadId& aThreadId) override;
+  mozilla::ipc::IPCResult RecvCreateVRProcess() override;
 
   mozilla::ipc::IPCResult RecvAccumulateChildHistograms(InfallibleTArray<HistogramAccumulation>&& aAccumulations) override;
   mozilla::ipc::IPCResult RecvAccumulateChildKeyedHistograms(InfallibleTArray<KeyedHistogramAccumulation>&& aAccumulations) override;
   mozilla::ipc::IPCResult RecvUpdateChildScalars(InfallibleTArray<ScalarAction>&& aScalarActions) override;
   mozilla::ipc::IPCResult RecvUpdateChildKeyedScalars(InfallibleTArray<KeyedScalarAction>&& aScalarActions) override;
   mozilla::ipc::IPCResult RecvRecordChildEvents(nsTArray<ChildEventData>&& events) override;
   mozilla::ipc::IPCResult RecvRecordDiscardedData(const DiscardedData& aDiscardedData) override;
 

--- a/gfx/ipc/GPUParent.cpp
+++ b/gfx/ipc/GPUParent.cpp
@@ -36,16 +36,17 @@
 #include "mozilla/webrender/RenderThread.h"
 #include "mozilla/webrender/WebRenderAPI.h"
 #include "mozilla/HangDetails.h"
 #include "nsDebugImpl.h"
 #include "nsIGfxInfo.h"
 #include "nsThreadManager.h"
 #include "prenv.h"
 #include "ProcessUtils.h"
+#include "VRGPUChild.h"
 #include "VRManager.h"
 #include "VRManagerParent.h"
 #include "VRThread.h"
 #include "VsyncBridgeParent.h"
 #if defined(XP_WIN)
 # include "mozilla/gfx/DeviceManagerDx.h"
 # include <process.h>
 # include <dwrite.h>
@@ -302,16 +303,23 @@ GPUParent::RecvInitImageBridge(Endpoint<
 mozilla::ipc::IPCResult
 GPUParent::RecvInitVRManager(Endpoint<PVRManagerParent>&& aEndpoint)
 {
   VRManagerParent::CreateForGPUProcess(std::move(aEndpoint));
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
+GPUParent::RecvInitVR(Endpoint<PVRGPUChild>&& aEndpoint)
+{
+  gfx::VRGPUChild::InitForGPUProcess(std::move(aEndpoint));
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
 GPUParent::RecvInitUiCompositorController(const LayersId& aRootLayerTreeId, Endpoint<PUiCompositorControllerParent>&& aEndpoint)
 {
   UiCompositorControllerParent::Start(aRootLayerTreeId, std::move(aEndpoint));
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
 GPUParent::RecvInitProfiler(Endpoint<PProfilerChild>&& aEndpoint)
@@ -460,16 +468,25 @@ GPUParent::RecvRequestMemoryReport(const
 {
   nsPrintfCString processName("GPU (pid %u)", (unsigned)getpid());
 
   mozilla::dom::MemoryReportRequestClient::Start(
     aGeneration, aAnonymize, aMinimizeMemoryUsage, aDMDFile, processName);
   return IPC_OK();
 }
 
+mozilla::ipc::IPCResult
+GPUParent::RecvShutdownVR()
+{
+  if (gfxPrefs::VRProcessEnabled()) {
+    VRGPUChild::ShutDown();
+  }
+  return IPC_OK();
+}
+
 void
 GPUParent::ActorDestroy(ActorDestroyReason aWhy)
 {
   if (AbnormalShutdown == aWhy) {
     NS_WARNING("Shutting down GPU process early due to a crash!");
     ProcessChild::QuickExit();
   }
 

--- a/gfx/ipc/GPUParent.h
+++ b/gfx/ipc/GPUParent.h
@@ -38,16 +38,17 @@ public:
   mozilla::ipc::IPCResult RecvInit(nsTArray<GfxPrefSetting>&& prefs,
                                    nsTArray<GfxVarUpdate>&& vars,
                                    const DevicePrefs& devicePrefs,
                                    nsTArray<LayerTreeIdMapping>&& mappings) override;
   mozilla::ipc::IPCResult RecvInitCompositorManager(Endpoint<PCompositorManagerParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvInitVsyncBridge(Endpoint<PVsyncBridgeParent>&& aVsyncEndpoint) override;
   mozilla::ipc::IPCResult RecvInitImageBridge(Endpoint<PImageBridgeParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvInitVRManager(Endpoint<PVRManagerParent>&& aEndpoint) override;
+  mozilla::ipc::IPCResult RecvInitVR(Endpoint<PVRGPUChild>&& aVRGPUChild) override;
   mozilla::ipc::IPCResult RecvInitUiCompositorController(const LayersId& aRootLayerTreeId, Endpoint<PUiCompositorControllerParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvInitProfiler(Endpoint<PProfilerChild>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvUpdatePref(const GfxPrefSetting& pref) override;
   mozilla::ipc::IPCResult RecvUpdateVar(const GfxVarUpdate& pref) override;
   mozilla::ipc::IPCResult RecvNewContentCompositorManager(Endpoint<PCompositorManagerParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvNewContentImageBridge(Endpoint<PImageBridgeParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvNewContentVRManager(Endpoint<PVRManagerParent>&& aEndpoint) override;
   mozilla::ipc::IPCResult RecvNewContentVideoDecoderManager(Endpoint<PVideoDecoderManagerParent>&& aEndpoint) override;
@@ -56,16 +57,17 @@ public:
   mozilla::ipc::IPCResult RecvAddLayerTreeIdMapping(const LayerTreeIdMapping& aMapping) override;
   mozilla::ipc::IPCResult RecvRemoveLayerTreeIdMapping(const LayerTreeIdMapping& aMapping) override;
   mozilla::ipc::IPCResult RecvNotifyGpuObservers(const nsCString& aTopic) override;
   mozilla::ipc::IPCResult RecvRequestMemoryReport(
     const uint32_t& generation,
     const bool& anonymize,
     const bool& minimizeMemoryUsage,
     const MaybeFileDesc& DMDFile) override;
+  mozilla::ipc::IPCResult RecvShutdownVR() override;
 
   void ActorDestroy(ActorDestroyReason aWhy) override;
 
 private:
   const TimeStamp mLaunchTime;
   RefPtr<VsyncBridgeParent> mVsyncBridge;
 #ifdef MOZ_GECKO_PROFILER
   RefPtr<ChildProfilerController> mProfilerController;

--- a/gfx/ipc/GPUProcessHost.cpp
+++ b/gfx/ipc/GPUProcessHost.cpp
@@ -155,16 +155,18 @@ GPUProcessHost::InitAfterConnect(bool aS
 void
 GPUProcessHost::Shutdown()
 {
   MOZ_ASSERT(!mShutdownRequested);
 
   mListener = nullptr;
 
   if (mGPUChild) {
+    mGPUChild->SendShutdownVR();
+
     // OnChannelClosed uses this to check if the shutdown was expected or
     // unexpected.
     mShutdownRequested = true;
 
     // The channel might already be closed if we got here unexpectedly.
     if (!mChannelClosed) {
       mGPUChild->Close();
     }

--- a/gfx/ipc/GraphicsMessages.ipdlh
+++ b/gfx/ipc/GraphicsMessages.ipdlh
@@ -10,16 +10,29 @@ using struct mozilla::null_t from "ipc/I
 using mozilla::gfx::FeatureStatus from "gfxTelemetry.h";
 using mozilla::gfx::BackendType from "mozilla/gfx/Types.h";
 using mozilla::gfx::IntSize from "mozilla/gfx/Point.h";
 using gfxImageFormat from "mozilla/gfx/Types.h";
 
 namespace mozilla {
 namespace gfx {
 
+union GfxPrefValue {
+  bool;
+  int32_t;
+  uint32_t;
+  float;
+  nsCString;
+};
+
+struct GfxPrefSetting {
+  int32_t index;
+  GfxPrefValue value;
+};
+
 struct D3D11DeviceStatus
 {
   bool isWARP;
   bool textureSharingWorks;
   uint32_t featureLevel;
   DxgiAdapterDesc adapter;
   int32_t sequenceNumber;
   bool useNV12;

--- a/gfx/ipc/PGPU.ipdl
+++ b/gfx/ipc/PGPU.ipdl
@@ -5,16 +5,17 @@
 
 include GraphicsMessages;
 include MemoryReportTypes;
 include HangTypes;
 include protocol PAPZInputBridge;
 include protocol PCompositorManager;
 include protocol PImageBridge;
 include protocol PProfiler;
+include protocol PVRGPU;
 include protocol PVRManager;
 include protocol PVsyncBridge;
 include protocol PUiCompositorController;
 include protocol PVideoDecoderManager;
 
 using base::ProcessId from "base/process.h";
 using mozilla::dom::NativeThreadId from "mozilla/dom/TabMessageUtils.h";
 using mozilla::Telemetry::HistogramAccumulation from "mozilla/TelemetryComms.h";
@@ -25,29 +26,16 @@ using mozilla::Telemetry::ChildEventData
 using mozilla::Telemetry::DiscardedData from "mozilla/TelemetryComms.h";
 using mozilla::gfx::Feature from "gfxFeature.h";
 using mozilla::gfx::Fallback from "gfxFallback.h";
 using mozilla::layers::LayersId from "mozilla/layers/LayersTypes.h";
 
 namespace mozilla {
 namespace gfx {
 
-union GfxPrefValue {
-  bool;
-  int32_t;
-  uint32_t;
-  float;
-  nsCString;
-};
-
-struct GfxPrefSetting {
-  int32_t index;
-  GfxPrefValue value;
-};
-
 struct LayerTreeIdMapping {
   LayersId layersId;
   ProcessId ownerId;
 };
 
 // This protocol allows the UI process to talk to the GPU process. There is one
 // instance of this protocol, with the GPUParent living on the main thread of
 // the GPU process and the GPUChild living on the main thread of the UI process.
@@ -67,17 +55,18 @@ parent:
              LayerTreeIdMapping[] mapping);
 
   async InitCompositorManager(Endpoint<PCompositorManagerParent> endpoint);
   async InitVsyncBridge(Endpoint<PVsyncBridgeParent> endpoint);
   async InitImageBridge(Endpoint<PImageBridgeParent> endpoint);
   async InitVRManager(Endpoint<PVRManagerParent> endpoint);
   async InitUiCompositorController(LayersId rootLayerTreeId, Endpoint<PUiCompositorControllerParent> endpoint);
   async InitProfiler(Endpoint<PProfilerChild> endpoint);
-
+  // Forward GPU process its endpoints to the VR process.
+  async InitVR(Endpoint<PVRGPUChild> endpoint);
   // Called to update a gfx preference or variable.
   async UpdatePref(GfxPrefSetting pref);
   async UpdateVar(GfxVarUpdate var);
 
   // Create a new content-process compositor bridge.
   async NewContentCompositorManager(Endpoint<PCompositorManagerParent> endpoint);
   async NewContentImageBridge(Endpoint<PImageBridgeParent> endpoint);
   async NewContentVRManager(Endpoint<PVRManagerParent> endpoint);
@@ -98,30 +87,33 @@ parent:
   // Have a message be broadcasted to the GPU process by the GPU process
   // observer service.
   async NotifyGpuObservers(nsCString aTopic);
 
   async RequestMemoryReport(uint32_t generation,
                             bool anonymize,
                             bool minimizeMemoryUsage,
                             MaybeFileDesc DMDFile);
+  async ShutdownVR();
 
 child:
   // Sent when the GPU process has initialized devices. This occurs once, after
   // Init().
   async InitComplete(GPUDeviceData data);
 
   // Sent when APZ detects checkerboarding and apz checkerboard reporting is enabled.
   async ReportCheckerboard(uint32_t severity, nsCString log);
 
   // Graphics errors, analogous to PContent::GraphicsError
   async GraphicsError(nsCString aError);
 
   async InitCrashReporter(Shmem shmem, NativeThreadId threadId);
 
+  async CreateVRProcess();
+
   // Have a message be broadcasted to the UI process by the UI process
   // observer service.
   async NotifyUiObservers(nsCString aTopic);
 
   // Messages for reporting telemetry to the UI process.
   async AccumulateChildHistograms(HistogramAccumulation[] accumulations);
   async AccumulateChildKeyedHistograms(KeyedHistogramAccumulation[] accumulations);
   async UpdateChildScalars(ScalarAction[] actions);

--- a/gfx/thebes/DeviceManagerDx.cpp
+++ b/gfx/thebes/DeviceManagerDx.cpp
@@ -149,16 +149,17 @@ DeviceManagerDx::ReleaseD3D11()
   mD3D11Module.reset();
   sD3D11CreateDeviceFn = nullptr;
 }
 
 static inline bool
 ProcessOwnsCompositor()
 {
   return XRE_GetProcessType() == GeckoProcessType_GPU ||
+         XRE_GetProcessType() == GeckoProcessType_VR ||
          (XRE_IsParentProcess() && !gfxConfig::IsEnabled(Feature::GPU_PROCESS));
 }
 
 bool
 DeviceManagerDx::CreateCompositorDevices()
 {
   MOZ_ASSERT(ProcessOwnsCompositor());
 

--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -26,16 +26,17 @@
 
 #include "gfxCrashReporterUtils.h"
 #include "gfxPlatform.h"
 #include "gfxPrefs.h"
 #include "gfxEnv.h"
 #include "gfxTextRun.h"
 #include "gfxUserFontSet.h"
 #include "gfxConfig.h"
+#include "VRProcessManager.h"
 #include "VRThread.h"
 
 #ifdef XP_WIN
 #include <process.h>
 #define getpid _getpid
 #else
 #include <unistd.h>
 #endif
@@ -998,16 +999,17 @@ gfxPlatform::Shutdown()
     // We should only support the default GL provider on Windows; then, this
     // could go away. Unfortunately, we currently support WGL (the default) for
     // WebGL on Optimus.
     GLContextProviderEGL::Shutdown();
 #endif
 
     if (XRE_IsParentProcess()) {
       GPUProcessManager::Shutdown();
+      VRProcessManager::Shutdown();
     }
 
     gfx::Factory::ShutDown();
 
     delete gGfxPlatformPrefsLock;
 
     gfxVars::Shutdown();
     gfxPrefs::DestroySingleton();

--- a/gfx/thebes/gfxPrefs.cpp
+++ b/gfx/thebes/gfxPrefs.cpp
@@ -8,16 +8,18 @@
 #include "MainThreadUtils.h"
 #include "nsXULAppAPI.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Unused.h"
 #include "mozilla/gfx/gfxVars.h"
 #include "mozilla/gfx/Logging.h"
 #include "mozilla/gfx/GPUChild.h"
 #include "mozilla/gfx/GPUProcessManager.h"
+#include "VRProcessManager.h"
+#include "VRChild.h"
 
 using namespace mozilla;
 
 nsTArray<gfxPrefs::Pref*>* gfxPrefs::sGfxPrefList = nullptr;
 gfxPrefs* gfxPrefs::sInstance = nullptr;
 bool gfxPrefs::sInstanceHasBeenDestroyed = false;
 
 gfxPrefs&
@@ -87,16 +89,23 @@ gfxPrefs::Pref::OnChange()
 {
   if (auto gpm = gfx::GPUProcessManager::Get()) {
     if (gfx::GPUChild* gpu = gpm->GetGPUChild()) {
       GfxPrefValue value;
       GetLiveValue(&value);
       Unused << gpu->SendUpdatePref(gfx::GfxPrefSetting(mIndex, value));
     }
   }
+  if (auto vpm = gfx::VRProcessManager::Get()) {
+    if (gfx::VRChild* vr = vpm->GetVRChild()) {
+      GfxPrefValue value;
+      GetLiveValue(&value);
+      Unused << vr->SendUpdatePref(gfx::GfxPrefSetting(mIndex, value));
+    }
+  }
   FireChangeCallback();
 }
 
 void
 gfxPrefs::Pref::FireChangeCallback()
 {
   if (mChangeCallback) {
     GfxPrefValue value;

--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -367,16 +367,17 @@ private:
   DECL_GFX_PREF(Live, "apz.scale_repaint_delay_ms",            APZScaleRepaintDelay, int32_t, 500);
 
   DECL_GFX_PREF(Live, "browser.ui.scroll-toolbar-threshold",   ToolbarScrollThreshold, int32_t, 10);
   DECL_GFX_PREF(Live, "browser.ui.zoom.force-user-scalable",   ForceUserScalable, bool, false);
   DECL_GFX_PREF(Live, "browser.viewport.desktopWidth",         DesktopViewportWidth, int32_t, 980);
 
   DECL_GFX_PREF(Live, "dom.ipc.plugins.asyncdrawing.enabled",  PluginAsyncDrawingEnabled, bool, false);
   DECL_GFX_PREF(Live, "dom.meta-viewport.enabled",             MetaViewportEnabled, bool, false);
+  DECL_GFX_PREF(Live, "dom.visualviewport.enabled",            VisualViewportEnabled, bool, false);
   DECL_GFX_PREF(Once, "dom.vr.enabled",                        VREnabled, bool, false);
   DECL_GFX_PREF(Live, "dom.vr.autoactivate.enabled",           VRAutoActivateEnabled, bool, false);
   DECL_GFX_PREF(Live, "dom.vr.controller_trigger_threshold",   VRControllerTriggerThreshold, float, 0.1f);
   DECL_GFX_PREF(Once, "dom.vr.external.enabled",               VRExternalEnabled, bool, true);
   DECL_GFX_PREF(Live, "dom.vr.navigation.timeout",             VRNavigationTimeout, int32_t, 1000);
   DECL_GFX_PREF(Once, "dom.vr.oculus.enabled",                 VROculusEnabled, bool, true);
   DECL_GFX_PREF(Live, "dom.vr.oculus.invisible.enabled",       VROculusInvisibleEnabled, bool, true);
   DECL_GFX_PREF(Live, "dom.vr.oculus.present.timeout",         VROculusPresentTimeout, int32_t, 500);
@@ -386,16 +387,17 @@ private:
   DECL_GFX_PREF(Live, "dom.vr.controller.enumerate.interval",  VRControllerEnumerateInterval, int32_t, 1000);
   DECL_GFX_PREF(Live, "dom.vr.display.enumerate.interval",     VRDisplayEnumerateInterval, int32_t, 5000);
   DECL_GFX_PREF(Live, "dom.vr.inactive.timeout",               VRInactiveTimeout, int32_t, 5000);
   DECL_GFX_PREF(Live, "dom.vr.poseprediction.enabled",         VRPosePredictionEnabled, bool, true);
   DECL_GFX_PREF(Live, "dom.vr.require-gesture",                VRRequireGesture, bool, true);
   DECL_GFX_PREF(Live, "dom.vr.puppet.enabled",                 VRPuppetEnabled, bool, false);
   DECL_GFX_PREF(Live, "dom.vr.puppet.submitframe",             VRPuppetSubmitFrame, uint32_t, 0);
   DECL_GFX_PREF(Live, "dom.vr.display.rafMaxDuration",         VRDisplayRafMaxDuration, uint32_t, 50);
+  DECL_GFX_PREF(Once, "dom.vr.process.enabled",                VRProcessEnabled, bool, false);
   DECL_GFX_PREF(Once, "dom.vr.service.enabled",                VRServiceEnabled, bool, false);
   DECL_GFX_PREF(Live, "dom.w3c_pointer_events.enabled",        PointerEventsEnabled, bool, false);
 
   DECL_GFX_PREF(Live, "general.smoothScroll",                  SmoothScrollEnabled, bool, true);
   DECL_GFX_PREF(Live, "general.smoothScroll.currentVelocityWeighting",
                 SmoothScrollCurrentVelocityWeighting, float, 0.25);
   DECL_GFX_PREF(Live, "general.smoothScroll.durationToIntervalRatio",
                 SmoothScrollDurationToIntervalRatio, int32_t, 200);

--- a/gfx/vr/VRManager.cpp
+++ b/gfx/vr/VRManager.cpp
@@ -2,24 +2,26 @@
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 
 #include "VRManager.h"
 #include "VRManagerParent.h"
+#include "VRGPUChild.h"
 #include "VRThread.h"
 #include "gfxVR.h"
 #include "mozilla/ClearOnShutdown.h"
 #include "mozilla/dom/VRDisplay.h"
 #include "mozilla/dom/GamepadEventTypes.h"
 #include "mozilla/layers/TextureHost.h"
 #include "mozilla/layers/CompositorThread.h"
 #include "mozilla/Unused.h"
+#include "mozilla/gfx/GPUParent.h"
 
 #include "gfxPrefs.h"
 #include "gfxVR.h"
 #include "gfxVRExternal.h"
 #if defined(XP_WIN)
 #include "gfxVROculus.h"
 #endif
 #if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
@@ -43,26 +45,29 @@ namespace gfx {
 
 static StaticRefPtr<VRManager> sVRManagerSingleton;
 
 /*static*/ void
 VRManager::ManagerInit()
 {
   MOZ_ASSERT(NS_IsMainThread());
 
+  // TODO: We should make VRManager::ManagerInit
+  // be called when entering VR content pages.
   if (sVRManagerSingleton == nullptr) {
     sVRManagerSingleton = new VRManager();
     ClearOnShutdown(&sVRManagerSingleton);
   }
 }
 
 VRManager::VRManager()
   : mInitialized(false)
   , mVRDisplaysRequested(false)
   , mVRControllersRequested(false)
+  , mVRServiceStarted(false)
 {
   MOZ_COUNT_CTOR(VRManager);
   MOZ_ASSERT(sVRManagerSingleton == nullptr);
 
   RefPtr<VRSystemManager> mgr;
 
   /**
    * We must add the VRDisplayManager's to mManagers in a careful order to
@@ -76,17 +81,23 @@ VRManager::VRManager()
    *
    * OSVR will be used if Oculus SDK and OpenVR don't detect any HMDS,
    * to support everyone else.
    */
 
 #if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
   // The VR Service accesses all hardware from a separate process
   // and replaces the other VRSystemManager when enabled.
-  mVRService = VRService::Create();
+  if (!gfxPrefs::VRProcessEnabled()) {
+    mVRService = VRService::Create();
+  } else if (gfxPrefs::VRProcessEnabled() && XRE_IsGPUProcess()) {
+    gfx::GPUParent* gpu = GPUParent::GetSingleton();
+    MOZ_ASSERT(gpu);
+    Unused << gpu->SendCreateVRProcess();
+  }
   if (mVRService) {
     mExternalManager = VRSystemManagerExternal::Create(mVRService->GetAPIShmem());
   }
   if (mExternalManager) {
     mManagers.AppendElement(mExternalManager);
   }
 #endif
 
@@ -140,33 +151,49 @@ VRManager::~VRManager()
 void
 VRManager::Destroy()
 {
   mVRDisplays.Clear();
   mVRControllers.Clear();
   for (uint32_t i = 0; i < mManagers.Length(); ++i) {
     mManagers[i]->Destroy();
   }
-
+#if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+  if (mVRService) {
+    mVRService->Stop();
+    mVRService = nullptr;
+  }
+#endif
   mInitialized = false;
 }
 
 void
 VRManager::Shutdown()
 {
   mVRDisplays.Clear();
   mVRControllers.Clear();
   for (uint32_t i = 0; i < mManagers.Length(); ++i) {
     mManagers[i]->Shutdown();
   }
 #if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
   if (mVRService) {
     mVRService->Stop();
   }
+  if (gfxPrefs::VRProcessEnabled()) {
+    RefPtr<Runnable> task = NS_NewRunnableFunction(
+      "VRGPUChild::SendStopVRService",
+      [] () -> void {
+        VRGPUChild* vrGPUChild = VRGPUChild::Get();
+        vrGPUChild->SendStopVRService();
+    });
+
+    NS_DispatchToMainThread(task.forget());
+  }
 #endif
+  mVRServiceStarted = false;
 }
 
 void
 VRManager::Init()
 {
   mInitialized = true;
 }
 
@@ -344,18 +371,32 @@ VRManager::RefreshVRDisplays(bool aMustD
 {
   /**
   * If we aren't viewing WebVR content, don't enumerate
   * new hardware, as it will cause some devices to power on
   * or interrupt other VR activities.
   */
   if (mVRDisplaysRequested || aMustDispatch) {
 #if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
-    if (mVRService) {
-      mVRService->Start();
+    // Tell VR process to start VR service.
+    if (gfxPrefs::VRProcessEnabled() && !mVRServiceStarted) {
+      RefPtr<Runnable> task = NS_NewRunnableFunction(
+        "VRGPUChild::SendStartVRService",
+        [] () -> void {
+          VRGPUChild* vrGPUChild = VRGPUChild::Get();
+          vrGPUChild->SendStartVRService();
+      });
+
+      NS_DispatchToMainThread(task.forget());
+      mVRServiceStarted = true;
+    } else if (!gfxPrefs::VRProcessEnabled()){
+      if (mVRService) {
+        mVRService->Start();
+        mVRServiceStarted = true;
+      }
     }
 #endif
     EnumerateVRDisplays();
   }
 
   /**
    * VRSystemManager::GetHMDs will not activate new hardware
    * or result in interruption of other VR activities.

--- a/gfx/vr/VRManager.h
+++ b/gfx/vr/VRManager.h
@@ -97,14 +97,15 @@ private:
   TimeStamp mLastActiveTime;
   RefPtr<VRSystemManagerPuppet> mPuppetManager;
   RefPtr<VRSystemManagerExternal> mExternalManager;
 #if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
   RefPtr<VRService> mVRService;
 #endif
   bool mVRDisplaysRequested;
   bool mVRControllersRequested;
+  bool mVRServiceStarted;
 };
 
 } // namespace gfx
 } // namespace mozilla
 
 #endif // GFX_VR_MANAGER_H

--- a/gfx/vr/gfxVRExternal.cpp
+++ b/gfx/vr/gfxVRExternal.cpp
@@ -349,16 +349,20 @@ VRSystemManagerExternal::VRSystemManager
   mShmemFD = 0;
 #elif defined(XP_WIN)
   mShmemFile = NULL;
 #elif defined(MOZ_WIDGET_ANDROID)
   mDoShutdown = false;
   mExternalStructFailed = false;
   mEnumerationCompleted = false;
 #endif
+
+  if (!aAPIShmem) {
+    OpenShmem();
+  }
 }
 
 VRSystemManagerExternal::~VRSystemManagerExternal()
 {
   CloseShmem();
 }
 
 void
@@ -395,17 +399,24 @@ VRSystemManagerExternal::OpenShmem()
     // TODO - Implement logging
     mExternalShmem = NULL;
     CloseShmem();
     return;
   }
 
 #elif defined(XP_WIN)
   if (mShmemFile == NULL) {
-    mShmemFile = OpenFileMappingA(FILE_MAP_ALL_ACCESS, FALSE, kShmemName);
+    if (gfxPrefs::VRProcessEnabled()) {
+      mShmemFile = CreateFileMappingA(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0,
+                                      sizeof(VRExternalShmem), kShmemName);
+	    MOZ_ASSERT(GetLastError() == 0);
+    } else {
+      mShmemFile = OpenFileMappingA(FILE_MAP_ALL_ACCESS, FALSE, kShmemName);
+    }
+
     if (mShmemFile == NULL) {
       // TODO - Implement logging
       CloseShmem();
       return;
     }
   }
   LARGE_INTEGER length;
   length.QuadPart = sizeof(VRExternalShmem);
@@ -499,17 +510,18 @@ VRSystemManagerExternal::CloseShmem()
 VRSystemManagerExternal::Create(VRExternalShmem* aAPIShmem /* = nullptr*/)
 {
   MOZ_ASSERT(NS_IsMainThread());
 
   if (!gfxPrefs::VREnabled()) {
     return nullptr;
   }
 
-  if (!gfxPrefs::VRExternalEnabled() && aAPIShmem == nullptr) {
+  if ((!gfxPrefs::VRExternalEnabled() && aAPIShmem == nullptr) ||
+      !XRE_IsGPUProcess()) {
     return nullptr;
   }
 
   RefPtr<VRSystemManagerExternal> manager = new VRSystemManagerExternal(aAPIShmem);
   return manager.forget();
 }
 
 void

--- a/gfx/vr/gfxVRExternal.h
+++ b/gfx/vr/gfxVRExternal.h
@@ -114,17 +114,17 @@ protected:
   virtual ~VRSystemManagerExternal();
 
 private:
   // there can only be one
   RefPtr<impl::VRDisplayExternal> mDisplay;
 #if defined(XP_MACOSX)
   int mShmemFD;
 #elif defined(XP_WIN)
-  HANDLE mShmemFile;
+  base::ProcessHandle mShmemFile;
 #elif defined(MOZ_WIDGET_ANDROID)
   bool mDoShutdown;
   bool mExternalStructFailed;
   bool mEnumerationCompleted;
 #endif
 
   volatile VRExternalShmem* mExternalShmem;
 #if !defined(MOZ_WIDGET_ANDROID)

--- a/gfx/vr/gfxVRPuppet.h
+++ b/gfx/vr/gfxVRPuppet.h
@@ -9,20 +9,28 @@
 
 #include "nsTArray.h"
 #include "mozilla/RefPtr.h"
 #include "nsRefPtrHashtable.h"
 
 #include "gfxVR.h"
 #include "VRDisplayLocal.h"
 
+#if defined(XP_WIN)
+#include "CompositorD3D11.h"
+#endif
+
 #if defined(XP_MACOSX)
 class MacIOSurface;
 #endif
 namespace mozilla {
+namespace layers {
+struct VertexShaderConstants;
+struct PixelShaderConstants;
+}
 namespace gfx {
 namespace impl {
 
 class VRDisplayPuppet : public VRDisplayLocal
 {
 public:
   void SetDisplayInfo(const VRDisplayInfo& aDisplayInfo);
   void SetSensorState(const VRHMDSensorState& aSensorState);

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/PVR.ipdl
@@ -0,0 +1,26 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+using mozilla::TimeStamp from "mozilla/TimeStamp.h";
+
+include GraphicsMessages;
+include protocol PVRGPU;
+
+namespace mozilla {
+namespace gfx {
+
+async protocol PVR
+{
+parent:
+  async NewGPUVRManager(Endpoint<PVRGPUParent> endpoint);
+  async Init(GfxPrefSetting[] prefs, GfxVarUpdate[] vars, DevicePrefs devicePrefs);
+  async NotifyVsync(TimeStamp vsyncTimestamp);
+
+  async UpdatePref(GfxPrefSetting pref);
+  async UpdateVar(GfxVarUpdate var);
+};
+
+} // namespace gfx
+} // namespace mozilla
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/PVRGPU.ipdl
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+namespace mozilla {
+namespace gfx {
+
+// IPC for VR-Content process
+async protocol PVRGPU
+{
+parent:
+  async StartVRService();
+  async StopVRService();
+};
+
+} // gfx
+} // mozilla
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRChild.cpp
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VRChild.h"
+#include "VRProcessParent.h"
+#include "gfxConfig.h"
+
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/SystemGroup.h"
+#include "mozilla/VsyncDispatcher.h"
+
+namespace mozilla {
+namespace gfx {
+
+VRChild::VRChild(VRProcessParent* aHost)
+ : mHost(aHost)
+{
+  MOZ_ASSERT(XRE_IsParentProcess());
+}
+
+void
+VRChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  gfxVars::RemoveReceiver(this);
+  mHost->OnChannelClosed();
+  XRE_ShutdownChildProcess();
+}
+
+void
+VRChild::Init()
+{
+  // Build a list of prefs the VR process will need. Note that because we
+  // limit the VR process to prefs contained in gfxPrefs, we can simplify
+  // the message in two ways: one, we only need to send its index in gfxPrefs
+  // rather than its name, and two, we only need to send prefs that don't
+  // have their default value.
+  // Todo: Consider to make our own vrPrefs that we are interested in VR process.
+  nsTArray<GfxPrefSetting> prefs;
+  for (auto pref : gfxPrefs::all()) {
+    if (pref->HasDefaultValue()) {
+      continue;
+    }
+
+    GfxPrefValue value;
+    pref->GetCachedValue(&value);
+    prefs.AppendElement(GfxPrefSetting(pref->Index(), value));
+  }
+  nsTArray<GfxVarUpdate> updates = gfxVars::FetchNonDefaultVars();
+
+  DevicePrefs devicePrefs;
+  devicePrefs.hwCompositing() = gfxConfig::GetValue(Feature::HW_COMPOSITING);
+  devicePrefs.d3d11Compositing() = gfxConfig::GetValue(Feature::D3D11_COMPOSITING);
+  devicePrefs.oglCompositing() = gfxConfig::GetValue(Feature::OPENGL_COMPOSITING);
+  devicePrefs.advancedLayers() = gfxConfig::GetValue(Feature::ADVANCED_LAYERS);
+  devicePrefs.useD2D1() = gfxConfig::GetValue(Feature::DIRECT2D);
+
+  SendInit(prefs, updates, devicePrefs);
+  gfxVars::AddReceiver(this);
+}
+
+void
+VRChild::OnVarChanged(const GfxVarUpdate& aVar)
+{
+  SendUpdateVar(aVar);
+}
+
+class DeferredDeleteVRChild : public Runnable
+{
+public:
+  explicit DeferredDeleteVRChild(UniquePtr<VRChild>&& aChild)
+    : Runnable("gfx::DeferredDeleteVRChild")
+    , mChild(std::move(aChild))
+  {
+  }
+
+  NS_IMETHODIMP Run() override {
+    return NS_OK;
+  }
+
+private:
+  UniquePtr<VRChild> mChild;
+};
+
+/* static */ void
+VRChild::Destroy(UniquePtr<VRChild>&& aChild)
+{
+  NS_DispatchToMainThread(new DeferredDeleteVRChild(std::move(aChild)));
+}
+
+} // namespace gfx
+} // namespace mozilla
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRChild.h
@@ -0,0 +1,42 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_VR_CHILD_H
+#define GFX_VR_CHILD_H
+
+#include "mozilla/gfx/PVRChild.h"
+#include "mozilla/gfx/gfxVarReceiver.h"
+#include "mozilla/VsyncDispatcher.h"
+
+namespace mozilla {
+namespace gfx {
+
+class VRProcessParent;
+class VRChild;
+
+class VRChild final
+ : public PVRChild,
+   public gfxVarReceiver {
+
+public:
+  explicit VRChild(VRProcessParent* aHost);
+  ~VRChild() = default;
+
+  static void Destroy(UniquePtr<VRChild>&& aChild);
+  void Init();
+  virtual void OnVarChanged(const GfxVarUpdate& aVar) override;
+
+protected:
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
+
+private:
+  VRProcessParent* mHost;
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif  // GFX_VR_CHILD_H
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRGPUChild.cpp
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VRGPUChild.h"
+
+
+namespace mozilla {
+namespace gfx {
+
+static StaticRefPtr<VRGPUChild> sVRGPUChildSingleton;
+
+/* static */ bool
+VRGPUChild::InitForGPUProcess(Endpoint<PVRGPUChild>&& aEndpoint)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!sVRGPUChildSingleton);
+
+  RefPtr<VRGPUChild> child(new VRGPUChild());
+  if (!aEndpoint.Bind(child)) {
+    return false;
+  }
+  sVRGPUChildSingleton = child;
+  return true;
+}
+
+/* static */ bool
+VRGPUChild::IsCreated()
+{
+  return !!sVRGPUChildSingleton;
+}
+
+/* static */ VRGPUChild*
+VRGPUChild::Get()
+{
+  MOZ_ASSERT(IsCreated(), "VRGPUChild haven't initialized yet.");
+  return sVRGPUChildSingleton;
+}
+
+/*static*/ void
+VRGPUChild::ShutDown()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (sVRGPUChildSingleton) {
+    sVRGPUChildSingleton->Destroy();
+    sVRGPUChildSingleton = nullptr;
+  }
+}
+
+class DeferredDeleteVRGPUChild : public Runnable
+{
+public:
+  explicit DeferredDeleteVRGPUChild(RefPtr<VRGPUChild> aChild)
+    : Runnable("gfx::DeferredDeleteVRGPUChild")
+    , mChild(std::move(aChild))
+  {
+  }
+
+  NS_IMETHODIMP Run() override {
+    mChild->Close();
+    return NS_OK;
+  }
+
+private:
+  RefPtr<VRGPUChild> mChild;
+};
+
+void
+VRGPUChild::Destroy()
+{
+  // Keep ourselves alive until everything has been shut down
+  RefPtr<VRGPUChild> selfRef = this;
+  NS_DispatchToMainThread(new DeferredDeleteVRGPUChild(this));
+}
+
+} // namespace gfx
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRGPUChild.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_VR_GPU_CHILD_H
+#define GFX_VR_GPU_CHILD_H
+
+#include "mozilla/gfx/PVRGPUChild.h"
+
+namespace mozilla {
+namespace gfx {
+
+class VRGPUChild final : public PVRGPUChild
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VRGPUChild);
+
+  static VRGPUChild* Get();
+  static bool InitForGPUProcess(Endpoint<PVRGPUChild>&& aEndpoint);
+  static bool IsCreated();
+  static void ShutDown();
+
+protected:
+  explicit VRGPUChild() {}
+  ~VRGPUChild() {}
+
+  void Destroy();
+
+private:
+  DISALLOW_COPY_AND_ASSIGN(VRGPUChild);
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif // GFX_VR_GPU_CHILD_H
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRGPUParent.cpp
@@ -0,0 +1,99 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VRGPUParent.h"
+
+#include "mozilla/ipc/ProcessChild.h"
+
+
+namespace mozilla {
+namespace gfx {
+
+using namespace ipc;
+
+
+VRGPUParent::VRGPUParent(ProcessId aChildProcessId)
+{
+  MOZ_COUNT_CTOR(VRGPUParent);
+  MOZ_ASSERT(NS_IsMainThread());
+
+  SetOtherProcessId(aChildProcessId);
+}
+
+void
+VRGPUParent::ActorDestroy(ActorDestroyReason aWhy)
+{
+#if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+  if (mVRService) {
+    mVRService->Stop();
+    mVRService = nullptr;
+  }
+#endif
+
+  MessageLoop::current()->PostTask(
+  NewRunnableMethod("gfx::VRGPUParent::DeferredDestroy",
+                    this,
+                    &VRGPUParent::DeferredDestroy));
+}
+
+void
+VRGPUParent::DeferredDestroy()
+{
+  mSelfRef = nullptr;
+}
+
+/* static */ RefPtr<VRGPUParent>
+VRGPUParent::CreateForGPU(Endpoint<PVRGPUParent>&& aEndpoint)
+{
+  RefPtr<VRGPUParent> vcp = new VRGPUParent(aEndpoint.OtherPid());
+  MessageLoop::current()->PostTask(
+    NewRunnableMethod<Endpoint<PVRGPUParent>&&>(
+    "gfx::VRGPUParent::Bind",
+    vcp,
+    &VRGPUParent::Bind,
+    std::move(aEndpoint)));
+
+  return vcp;
+}
+
+void
+VRGPUParent::Bind(Endpoint<PVRGPUParent>&& aEndpoint)
+{
+  if (!aEndpoint.Bind(this)) {
+    return;
+  }
+
+  mSelfRef = this;
+}
+
+mozilla::ipc::IPCResult
+VRGPUParent::RecvStartVRService()
+{
+#if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+  mVRService = VRService::Create();
+  MOZ_ASSERT(mVRService);
+
+  mVRService->Start();
+#endif
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
+VRGPUParent::RecvStopVRService()
+{
+#if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+  if (mVRService) {
+    mVRService->Stop();
+    mVRService = nullptr;
+  }
+#endif
+
+  return IPC_OK();
+}
+
+} // namespace gfx
+} // namespace mozilla
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRGPUParent.h
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_VR_GPU_PARENT_H
+#define GFX_VR_GPU_PARENT_H
+
+#include "mozilla/gfx/PVRGPUParent.h"
+
+namespace mozilla {
+namespace gfx {
+
+class VRGPUParent final : public PVRGPUParent {
+   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VRGPUParent)
+
+public:
+  explicit VRGPUParent(ProcessId aChildProcessId);
+
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
+  static RefPtr<VRGPUParent> CreateForGPU(Endpoint<PVRGPUParent>&& aEndpoint);
+
+protected:
+  ~VRGPUParent() {}
+
+  void Bind(Endpoint<PVRGPUParent>&& aEndpoint);
+  virtual mozilla::ipc::IPCResult RecvStartVRService() override;
+  virtual mozilla::ipc::IPCResult RecvStopVRService() override;
+
+private:
+  void DeferredDestroy();
+
+  RefPtr<VRGPUParent> mSelfRef;
+#if defined(XP_WIN) || defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(MOZ_WIDGET_ANDROID))
+  RefPtr<VRService> mVRService;
+#endif
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif // GFX_VR_CONTENT_PARENT_H
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRParent.cpp
@@ -0,0 +1,143 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VRParent.h"
+#include "VRGPUParent.h"
+#include "VRManager.h"
+#include "gfxConfig.h"
+
+#include "mozilla/gfx/gfxVars.h"
+#include "mozilla/ipc/ProcessChild.h"
+
+#if defined(XP_WIN)
+#include "mozilla/gfx/DeviceManagerDx.h"
+#endif
+
+namespace mozilla {
+namespace gfx {
+
+using mozilla::ipc::IPCResult;
+
+VRParent::VRParent()
+ : mVRGPUParent(nullptr)
+{
+}
+
+IPCResult
+VRParent::RecvNewGPUVRManager(Endpoint<PVRGPUParent>&& aEndpoint)
+{
+  RefPtr<VRGPUParent> vrGPUParent = VRGPUParent::CreateForGPU(std::move(aEndpoint));
+  if (!vrGPUParent) {
+    return IPC_FAIL_NO_REASON(this);
+  }
+
+  mVRGPUParent = std::move(vrGPUParent);
+  return IPC_OK();
+}
+
+IPCResult
+VRParent::RecvInit(nsTArray<GfxPrefSetting>&& prefs,
+                   nsTArray<GfxVarUpdate>&& vars,
+                   const DevicePrefs& devicePrefs)
+{
+  const nsTArray<gfxPrefs::Pref*>& globalPrefs = gfxPrefs::all();
+  for (auto& setting : prefs) {
+    gfxPrefs::Pref* pref = globalPrefs[setting.index()];
+    pref->SetCachedValue(setting.value());
+  }
+  for (const auto& var : vars) {
+    gfxVars::ApplyUpdate(var);
+  }
+
+  // Inherit device preferences.
+  gfxConfig::Inherit(Feature::HW_COMPOSITING, devicePrefs.hwCompositing());
+  gfxConfig::Inherit(Feature::D3D11_COMPOSITING, devicePrefs.d3d11Compositing());
+  gfxConfig::Inherit(Feature::OPENGL_COMPOSITING, devicePrefs.oglCompositing());
+  gfxConfig::Inherit(Feature::ADVANCED_LAYERS, devicePrefs.advancedLayers());
+  gfxConfig::Inherit(Feature::DIRECT2D, devicePrefs.useD2D1());
+
+#if defined(XP_WIN)
+  if (gfxConfig::IsEnabled(Feature::D3D11_COMPOSITING)) {
+    DeviceManagerDx::Get()->CreateCompositorDevices();
+  }
+#endif
+  return IPC_OK();
+}
+
+IPCResult
+VRParent::RecvNotifyVsync(const TimeStamp& vsyncTimestamp)
+{
+  VRManager* vm = VRManager::Get();
+  vm->NotifyVsync(vsyncTimestamp);
+  return IPC_OK();
+}
+
+IPCResult
+VRParent::RecvUpdatePref(const GfxPrefSetting& setting)
+{
+  gfxPrefs::Pref* pref = gfxPrefs::all()[setting.index()];
+  pref->SetCachedValue(setting.value());
+  return IPC_OK();
+}
+
+IPCResult
+VRParent::RecvUpdateVar(const GfxVarUpdate& aUpdate)
+{
+  gfxVars::ApplyUpdate(aUpdate);
+  return IPC_OK();
+}
+
+void
+VRParent::ActorDestroy(ActorDestroyReason aWhy)
+{
+  if (AbnormalShutdown == aWhy) {
+    NS_WARNING("Shutting down VR process early due to a crash!");
+    ProcessChild::QuickExit();
+  }
+
+  mVRGPUParent->Close();
+#if defined(XP_WIN)
+  DeviceManagerDx::Shutdown();
+#endif
+  gfxVars::Shutdown();
+  gfxConfig::Shutdown();
+  gfxPrefs::DestroySingleton();
+  XRE_ShutdownChildProcess();
+}
+
+bool
+VRParent::Init(base::ProcessId aParentPid,
+               const char* aParentBuildID,
+               MessageLoop* aIOLoop,
+               IPC::Channel* aChannel)
+{
+  // Now it's safe to start IPC.
+  if (NS_WARN_IF(!Open(aChannel, aParentPid, aIOLoop))) {
+    return false;
+  }
+
+  // This must be checked before any IPDL message, which may hit sentinel
+  // errors due to parent and content processes having different
+  // versions.
+  MessageChannel* channel = GetIPCChannel();
+  if (channel && !channel->SendBuildIDsMatchMessage(aParentBuildID)) {
+    // We need to quit this process if the buildID doesn't match the parent's.
+    // This can occur when an update occurred in the background.
+    ProcessChild::QuickExit();
+  }
+
+  // Ensure gfxPrefs are initialized.
+  gfxPrefs::GetSingleton();
+  gfxConfig::Init();
+  gfxVars::Initialize();
+#if defined(XP_WIN)
+  DeviceManagerDx::Init();
+#endif
+  return true;
+}
+
+} // namespace gfx
+} // namespace mozilla
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRParent.h
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_VR_PARENT_H
+#define GFX_VR_PARENT_H
+
+#include "mozilla/gfx/PVRParent.h"
+
+namespace mozilla {
+namespace gfx {
+
+class VRGPUParent;
+class VRService;
+class VRSystemManagerExternal;
+
+class VRParent final : public PVRParent {
+
+public:
+  VRParent();
+  bool Init(base::ProcessId aParentPid,
+            const char* aParentBuildID,
+            MessageLoop* aIOLoop,
+            IPC::Channel* aChannel);
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
+
+protected:
+  virtual mozilla::ipc::IPCResult RecvNewGPUVRManager(Endpoint<PVRGPUParent>&& aEndpoint) override;
+  virtual mozilla::ipc::IPCResult RecvInit(nsTArray<GfxPrefSetting>&& prefs,
+                                           nsTArray<GfxVarUpdate>&& vars,
+                                           const DevicePrefs& devicePrefs) override;
+  virtual mozilla::ipc::IPCResult RecvNotifyVsync(const TimeStamp& vsyncTimestamp) override;
+  virtual mozilla::ipc::IPCResult RecvUpdatePref(const GfxPrefSetting& setting) override;
+  virtual mozilla::ipc::IPCResult RecvUpdateVar(const GfxVarUpdate& pref) override;
+
+private:
+  RefPtr<VRGPUParent> mVRGPUParent;
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif // GFX_VR_PARENT_H
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRProcessChild.cpp
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VRProcessChild.h"
+
+#include "mozilla/BackgroundHangMonitor.h"
+#include "mozilla/ipc/IOThreadChild.h"
+
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+using mozilla::ipc::IOThreadChild;
+
+
+VRProcessChild::VRProcessChild(ProcessId aParentPid)
+  : ProcessChild(aParentPid)
+#if defined(aParentPid)
+  , mVR(nullptr)
+#endif
+{
+}
+
+VRProcessChild::~VRProcessChild()
+{
+}
+
+bool
+VRProcessChild::Init(int aArgc, char* aArgv[])
+{
+  BackgroundHangMonitor::Startup();
+
+  char* parentBuildID = nullptr;
+  for (int i = 1; i < aArgc; i++) {
+    if (strcmp(aArgv[i], "-parentBuildID") == 0) {
+      parentBuildID = aArgv[i + 1];
+    }
+  }
+
+  mVR.Init(ParentPid(), parentBuildID,
+           IOThreadChild::message_loop(),
+           IOThreadChild::channel());
+
+  return true;
+}
+
+void
+VRProcessChild::CleanUp()
+{
+  NS_ShutdownXPCOM(nullptr);
+}
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRProcessChild.h
@@ -0,0 +1,43 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GFX_VR_PROCESS_CHILD_H
+#define GFX_VR_PROCESS_CHILD_H
+
+#include "mozilla/ipc/ProcessChild.h"
+#include "VRParent.h"
+
+
+namespace mozilla {
+namespace gfx {
+
+/**
+ * Contains the VRChild object that facilitates IPC communication to/from
+ * the instance of the VR library that is run in this process.
+ */
+class VRProcessChild final : public mozilla::ipc::ProcessChild
+{
+protected:
+  typedef mozilla::ipc::ProcessChild ProcessChild;
+
+public:
+  explicit VRProcessChild(ProcessId aParentPid);
+  ~VRProcessChild();
+
+  // ProcessChild functions.
+  virtual bool Init(int aArgc, char* aArgv[]) override;
+  virtual void CleanUp() override;
+
+private:
+  DISALLOW_COPY_AND_ASSIGN(VRProcessChild);
+
+  VRParent mVR;
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif /* GFX_VR_PROCESS_CHILD_H */
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRProcessManager.cpp
@@ -0,0 +1,171 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "VRProcessManager.h"
+
+#include "VRProcessParent.h"
+#include "VRChild.h"
+#include "VRGPUChild.h"
+#include "VRGPUParent.h"
+
+
+namespace mozilla {
+namespace gfx {
+
+static StaticAutoPtr<VRProcessManager> sSingleton;
+
+/* static */ VRProcessManager*
+VRProcessManager::Get()
+{
+  return sSingleton;
+}
+
+/* static */ void
+VRProcessManager::Initialize()
+{
+  MOZ_ASSERT(XRE_IsParentProcess());
+  sSingleton = new VRProcessManager();
+}
+
+/* static */ void
+VRProcessManager::Shutdown()
+{
+  sSingleton = nullptr;
+}
+
+VRProcessManager::VRProcessManager()
+ : mProcess(nullptr)
+{
+  MOZ_COUNT_CTOR(VRProcessManager);
+
+  mObserver = new Observer(this);
+  nsContentUtils::RegisterShutdownObserver(mObserver);
+}
+
+VRProcessManager::~VRProcessManager()
+{
+  MOZ_COUNT_DTOR(VRProcessManager);
+
+  DestroyProcess();
+  // The VR process should have already been shut down.
+  MOZ_ASSERT(!mProcess);
+}
+
+void
+VRProcessManager::LaunchVRProcess()
+{
+  if (mProcess) {
+    return;
+  }
+
+  // The subprocess is launched asynchronously, so we wait for a callback to
+  // acquire the IPDL actor.
+  mProcess = new VRProcessParent();
+  if (!mProcess->Launch()) {
+    DisableVRProcess("Failed to launch VR process");
+  }
+}
+
+void
+VRProcessManager::DisableVRProcess(const char* aMessage)
+{
+  if (!gfxPrefs::VRProcessEnabled()) {
+    return;
+  }
+
+  DestroyProcess();
+}
+
+void
+VRProcessManager::DestroyProcess()
+{
+  if (!mProcess) {
+    return;
+  }
+
+  mProcess->Shutdown();
+  mProcess = nullptr;
+}
+
+bool
+VRProcessManager::CreateGPUBridges(base::ProcessId aOtherProcess,
+                                   mozilla::ipc::Endpoint<PVRGPUChild>* aOutVRBridge)
+{
+  if (!CreateGPUVRManager(aOtherProcess, aOutVRBridge)) {
+    return false;
+  }
+  return true;
+}
+
+bool
+VRProcessManager::CreateGPUVRManager(base::ProcessId aOtherProcess,
+                                     mozilla::ipc::Endpoint<PVRGPUChild>* aOutEndpoint)
+{
+  base::ProcessId vrparentPid = mProcess
+                                ? mProcess->OtherPid()  // VR process id.
+                                : base::GetCurrentProcId();
+
+  ipc::Endpoint<PVRGPUParent> vrparentPipe;
+  ipc::Endpoint<PVRGPUChild> vrchildPipe;
+  nsresult rv = PVRGPU::CreateEndpoints(vrparentPid,   // vr process id
+                                        aOtherProcess, // gpu process id
+                                        &vrparentPipe,
+                                        &vrchildPipe);
+
+  if (NS_FAILED(rv)) {
+	  gfxCriticalNote << "Could not create gpu-vr bridge: " << hexa(int(rv));
+	  return false;
+  }
+
+  // Bind vr-gpu pipe to VRParent and make a PVRGPU connection.
+  VRChild* vrChild = mProcess->GetActor();
+  vrChild->SendNewGPUVRManager(std::move(vrparentPipe));
+
+  *aOutEndpoint = std::move(vrchildPipe);
+  return true;
+}
+
+NS_IMPL_ISUPPORTS(VRProcessManager::Observer, nsIObserver);
+
+VRProcessManager::Observer::Observer(VRProcessManager* aManager)
+ : mManager(aManager)
+{
+}
+
+NS_IMETHODIMP
+VRProcessManager::Observer::Observe(nsISupports* aSubject, const char* aTopic, const char16_t* aData)
+{
+  if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    mManager->OnXPCOMShutdown();
+  }
+  return NS_OK;
+}
+
+void
+VRProcessManager::CleanShutdown()
+{
+  DestroyProcess();
+}
+
+void
+VRProcessManager::OnXPCOMShutdown()
+{
+  if (mObserver) {
+    nsContentUtils::UnregisterShutdownObserver(mObserver);
+    mObserver = nullptr;
+  }
+
+  CleanShutdown();
+}
+
+VRChild*
+VRProcessManager::GetVRChild()
+{
+  return mProcess->GetActor();
+}
+
+} // namespace gfx
+} // namespace mozilla
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/gfx/vr/ipc/VRProcessManager.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GFX_VR_PROCESS_MANAGER_H
+#define GFX_VR_PROCESS_MANAGER_H
+
+
+namespace mozilla {
+namespace gfx {
+
+class VRProcessParent;
+class VRManagerChild;
+class PVRGPUChild;
+class VRChild;
+
+// The VRProcessManager is a singleton responsible for creating VR-bound
+// objects that may live in another process.
+class VRProcessManager final
+{
+public:
+  static VRProcessManager* Get();
+  static void Initialize();
+  static void Shutdown();
+
+  ~VRProcessManager();
+
+  // If not using a VR process, launch a new VR process asynchronously.
+  void LaunchVRProcess();
+  void DestroyProcess();
+
+  bool CreateGPUBridges(base::ProcessId aOtherProcess,
+                        mozilla::ipc::Endpoint<PVRGPUChild>* aOutVRBridge);
+
+  VRChild* GetVRChild();
+
+private:
+  VRProcessManager();
+
+  DISALLOW_COPY_AND_ASSIGN(VRProcessManager);
+
+  bool CreateGPUVRManager(base::ProcessId aOtherProcess,
+                              mozilla::ipc::Endpoint<PVRGPUChild>* aOutEndpoint);
+  void OnXPCOMShutdown();
+  void CleanShutdown();
+
+  // Permanently disable the VR process and record a message why.
+  void DisableVRProcess(const char* aMessage);
+
+  class Observer final : public nsIObserver {
+  public:
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+    explicit Observer(VRProcessManager* aManager);
+
+  protected:
+    ~Observer() {}
+
+    VRProcessManager* mManager;
+  };
+  friend class Observer;
+
+  RefPtr<Observer> mObserver;
+  VRProcessParent* mProcess;
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif // GFX_VR_PROCESS_MANAGER_H