new file mode 100644
--- /dev/null
+++ b/mobile/android/chrome/content/WebcompatReporter.js
@@ -0,0 +1,87 @@
+/* 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/. */
+
+const { classes: Cc, interfaces: Ci, utils: Cu } = Components;
+
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+var WebcompatReporter = {
+  menuItem: null,
+  menuItemEnabled: null,
+  init: function() {
+    Services.obs.addObserver(this, "DesktopMode:Change", false);
+    Services.obs.addObserver(this, "content-page-shown", false);
+    this.addMenuItem();
+  },
+
+  uninit: function() {
+    Services.obs.removeObserver(this, "DesktopMode:Change");
+
+    if (this.menuItem) {
+      NativeWindow.menu.remove(this.menuItem);
+      this.menuItem = null;
+    }
+  },
+
+  observe: function(subject, topic, data) {
+    if (topic === "content-page-shown") {
+      let currentURI = subject.documentURI;
+      if (!this.menuItemEnabled && this.isReportableUrl(currentURI)) {
+        NativeWindow.menu.update(this.menuItem, {enabled: true});
+        this.menuItemEnabled = true;
+      } else if (this.menuItemEnabled && !this.isReportableUrl(currentURI)) {
+        NativeWindow.menu.update(this.menuItem, {enabled: false});
+        this.menuItemEnabled = false;
+      }
+    } else if (topic === "DesktopMode:Change") {
+      let args = JSON.parse(data);
+      let tab = BrowserApp.getTabForId(args.tabId);
+      if (args.desktopMode && tab !== null) {
+        this.reportDesktopModePrompt();
+      }
+    }
+  },
+
+  addMenuItem: function() {
+    this.menuItem = NativeWindow.menu.add({
+      name: this.strings.GetStringFromName("webcompat.menu.name"),
+      callback: () => {
+        let currentURI = BrowserApp.selectedTab.browser.currentURI.spec;
+        this.reportIssue(currentURI);
+      },
+      enabled: false,
+    });
+  },
+
+  isReportableUrl: function(url) {
+    return url !== null && !(url.startsWith("about") ||
+                             url.startsWith("chrome") ||
+                             url.startsWith("file") ||
+                             url.startsWith("resource"));
+  },
+
+  reportDesktopModePrompt: function() {
+    let currentURI = BrowserApp.selectedTab.browser.currentURI.spec;
+    let message = this.strings.GetStringFromName("webcompat.reportDesktopMode.message");
+    let options = {
+      button: {
+        label: this.strings.GetStringFromName("webcompat.reportDesktopModeYes.label"),
+        callback: () => this.reportIssue(currentURI)
+      }
+    };
+    NativeWindow.toast.show(message, "long", options);
+  },
+
+  reportIssue: function(url) {
+    let webcompatURL = new URL("http://webcompat.com/");
+    webcompatURL.searchParams.append("open", "1");
+    webcompatURL.searchParams.append("url", url);
+    BrowserApp.addTab(webcompatURL.href);
+  }
+};
+
+XPCOMUtils.defineLazyGetter(WebcompatReporter, "strings", function() {
+  return Services.strings.createBundle("chrome://browser/locale/webcompatReporter.properties");
+});

--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -107,16 +107,19 @@ XPCOMUtils.defineLazyModuleGetter(this, 
   ["InputWidgetHelper", "chrome://browser/content/InputWidgetHelper.js"],
   ["AboutReader", "chrome://browser/content/aboutReader.js"],
   ["MasterPassword", "chrome://browser/content/MasterPassword.js"],
   ["PluginHelper", "chrome://browser/content/PluginHelper.js"],
   ["OfflineApps", "chrome://browser/content/OfflineApps.js"],
   ["Linkifier", "chrome://browser/content/Linkify.js"],
   ["ZoomHelper", "chrome://browser/content/ZoomHelper.js"],
   ["CastingApps", "chrome://browser/content/CastingApps.js"],
+#ifdef NIGHTLY_BUILD
+  ["WebcompatReporter", "chrome://browser/content/WebcompatReporter.js"],
+#endif
 ].forEach(function (aScript) {
   let [name, script] = aScript;
   XPCOMUtils.defineLazyGetter(window, name, function() {
     let sandbox = {};
     Services.scriptloader.loadSubScript(script, sandbox);
     return sandbox[name];
   });
 });
@@ -330,16 +333,19 @@ var BrowserApp = {
         }, Ci.nsIThread.DISPATCH_NORMAL);
 
 #ifdef MOZ_SAFE_BROWSING
         Services.tm.mainThread.dispatch(function() {
           // Bug 778855 - Perf regression if we do this here. To be addressed in bug 779008.
           SafeBrowsing.init();
         }, Ci.nsIThread.DISPATCH_NORMAL);
 #endif
+#ifdef NIGHTLY_BUILD
+        WebcompatReporter.init();
+#endif
       } catch(ex) { console.log(ex); }
     }, false);
 
     BrowserEventHandler.init();
     ViewportHandler.init();
 
     Services.androidBridge.browserApp = this;
 
@@ -853,16 +859,19 @@ var BrowserApp = {
     RemoteDebugger.uninit();
     Reader.uninit();
     UserAgentOverrides.uninit();
     DesktopUserAgent.uninit();
     ExternalApps.uninit();
     CastingApps.uninit();
     Distribution.uninit();
     Tabs.uninit();
+#ifdef NIGHTLY_BUILD
+    WebcompatReporter.uninit();
+#endif
   },
 
   // This function returns false during periods where the browser displayed document is
   // different from the browser content document, so user actions and some kinds of viewport
   // updates should be ignored. This period starts when we start loading a new page or
   // switch tabs, and ends when the new browser content document has been drawn and handed
   // off to the compositor.
   isBrowserContentDocumentDisplayed: function() {

--- a/mobile/android/chrome/jar.mn
+++ b/mobile/android/chrome/jar.mn
@@ -57,14 +57,17 @@ chrome.jar:
 #ifdef MOZ_SERVICES_HEALTHREPORT
   content/aboutHealthReport.xhtml      (content/aboutHealthReport.xhtml)
 * content/aboutHealthReport.js         (content/aboutHealthReport.js)
 #endif
 #ifdef MOZ_DEVICES
   content/aboutDevices.xhtml           (content/aboutDevices.xhtml)
   content/aboutDevices.js              (content/aboutDevices.js)
 #endif
+#ifdef NIGHTLY_BUILD
+  content/WebcompatReporter.js         (content/WebcompatReporter.js)
+#endif
 
 % content branding %content/branding/
 
 % override chrome://global/content/config.xul chrome://browser/content/config.xhtml
 % override chrome://global/content/netError.xhtml chrome://browser/content/netError.xhtml
 % override chrome://mozapps/content/extensions/extensions.xul chrome://browser/content/aboutAddons.xhtml

new file mode 100644
--- /dev/null
+++ b/mobile/android/locales/en-US/chrome/webcompatReporter.properties
@@ -0,0 +1,12 @@
+# 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/.
+
+# LOCALIZATION NOTE (webcompat.menu.name): A "site issue" is a bug, display,
+# or functionality problem with a webpage in the browser.
+webcompat.menu.name=Report Site Issue
+
+# LOCALIZATION NOTE (webcompat.reportDesktopMode.message): A " site issue" is a
+# bug, display, or functionality problem with a webpage in the browser.
+webcompat.reportDesktopMode.message=Report site issue?
+webcompat.reportDesktopModeYes.label=Report

--- a/mobile/android/locales/jar.mn
+++ b/mobile/android/locales/jar.mn
@@ -34,16 +34,19 @@
   locale/@AB_CD@/browser/sync.dtd                 (%chrome/sync.dtd)
   locale/@AB_CD@/browser/sync.properties          (%chrome/sync.properties)
   locale/@AB_CD@/browser/prompt.dtd               (%chrome/prompt.dtd)
   locale/@AB_CD@/browser/feedback.dtd             (%chrome/feedback.dtd)
   locale/@AB_CD@/browser/phishing.dtd             (%chrome/phishing.dtd)
   locale/@AB_CD@/browser/payments.properties      (%chrome/payments.properties)
   locale/@AB_CD@/browser/handling.properties      (%chrome/handling.properties)
   locale/@AB_CD@/browser/webapp.properties        (%chrome/webapp.properties)
+#ifdef NIGHTLY_BUILD
+  locale/@AB_CD@/browser/webcompatReporter.properties (%chrome/webcompatReporter.properties)
+#endif
 
 # overrides for toolkit l10n, also for en-US
 relativesrcdir toolkit/locales:
   locale/@AB_CD@/browser/overrides/about.dtd                       (%chrome/global/about.dtd)
   locale/@AB_CD@/browser/overrides/aboutAbout.dtd                  (%chrome/global/aboutAbout.dtd)
   locale/@AB_CD@/browser/overrides/aboutRights.dtd                 (%chrome/global/aboutRights.dtd)
   locale/@AB_CD@/browser/overrides/charsetMenu.properties          (%chrome/global/charsetMenu.properties)
   locale/@AB_CD@/browser/overrides/commonDialogs.properties        (%chrome/global/commonDialogs.properties)