--- a/browser/devtools/profiler/ProfilerPanel.jsm
+++ b/browser/devtools/profiler/ProfilerPanel.jsm
@@ -1,28 +1,30 @@
 /* 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/. */
 
 "use strict";
 
 const Cu = Components.utils;
 
+Cu.import("resource:///modules/devtools/gDevTools.jsm");
 Cu.import("resource:///modules/devtools/ProfilerController.jsm");
 Cu.import("resource:///modules/devtools/ProfilerHelpers.jsm");
 Cu.import("resource://gre/modules/commonjs/sdk/core/promise.js");
 Cu.import("resource:///modules/devtools/EventEmitter.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 this.EXPORTED_SYMBOLS = ["ProfilerPanel"];
 
-XPCOMUtils.defineLazyGetter(this, "DebuggerServer", function () {
-  Cu.import("resource://gre/modules/devtools/dbg-server.jsm");
-  return DebuggerServer;
-});
+XPCOMUtils.defineLazyModuleGetter(this, "DebuggerServer",
+  "resource://gre/modules/devtools/dbg-server.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+  "resource://gre/modules/Services.jsm");
 
 /**
  * An instance of a profile UI. Profile UI consists of
  * an iframe with Cleopatra loaded in it and some
  * surrounding meta-data (such as uids).
  *
  * Its main function is to talk to the Cleopatra instance
  * inside of the iframe.
@@ -100,16 +102,19 @@ function ProfileUI(uid, panel) {
           label.textContent = label.textContent.replace(/\s\*$/, "");
         }.bind(this));
         break;
       case "disabled":
         this.emit("disabled");
         break;
       case "enabled":
         this.emit("enabled");
+        break;
+      case "displaysource":
+        this.panel.displaySource(event.data.data);
     }
   }.bind(this));
 }
 
 ProfileUI.prototype = {
   show: function PUI_show() {
     this.iframe.removeAttribute("hidden");
   },
@@ -214,25 +219,41 @@ ProfilerPanel.prototype = {
   document:    null,
   target:      null,
   controller:  null,
   profiles:    null,
 
   _uid:        null,
   _activeUid:  null,
   _runningUid: null,
+  _browserWin: null,
 
   get activeProfile() {
     return this.profiles.get(this._activeUid);
   },
 
   set activeProfile(profile) {
     this._activeUid = profile.uid;
   },
 
+  get browserWindow() {
+    if (this._browserWin) {
+      return this._browserWin;
+    }
+
+    let win = this.window.top;
+    let type = win.document.documentElement.getAttribute("windowtype");
+
+    if (type !== "navigator:browser") {
+      win = Services.wm.getMostRecentWindow("navigator:browser");
+    }
+
+    return this._browserWin = win;
+  },
+
   /**
    * Open a debug connection and, on success, switch to the newly created
    * profile.
    *
    * @return Promise
    */
   open: function PP_open() {
     let deferred = Promise.defer();
@@ -412,16 +433,58 @@ ProfilerPanel.prototype = {
           task: data.task
         }), "*");
       }
       uid -= 1;
     }
   },
 
   /**
+   * Open file specified in data in either a debugger or view-source.
+   *
+   * @param object data
+   *   An object describing the file. It must have three properties:
+   *    - uri
+   *    - line
+   *    - isChrome (chrome files are opened via view-source)
+   */
+  displaySource: function PP_displaySource(data, onOpen=function() {}) {
+    let win = this.window;
+    let panelWin, timeout;
+
+    function onSourceShown(event) {
+      if (event.detail.url !== data.uri) {
+        return;
+      }
+
+      panelWin.removeEventListener("Debugger:SourceShown", onSourceShown, false);
+      panelWin.editor.setCaretPosition(data.line - 1);
+      onOpen();
+    }
+
+    if (data.isChrome) {
+      return void this.browserWindow.gViewSourceUtils.
+        viewSource(data.uri, null, this.document, data.line);
+    }
+
+    gDevTools.showToolbox(this.target, "jsdebugger").then(function (toolbox) {
+      let dbg = toolbox.getCurrentPanel();
+      panelWin = dbg.panelWin;
+
+      let view = dbg.panelWin.DebuggerView;
+      if (view.Source && view.Sources.selectedValue === data.uri) {
+        return void view.editor.setCaretPosition(data.line - 1);
+      }
+
+      panelWin.addEventListener("Debugger:SourceShown", onSourceShown, false);
+      panelWin.DebuggerView.Sources.preferredSource = data.uri;
+    }.bind(this));
+  },
+
+  /**
    * Cleanup.
    */
   destroy: function PP_destroy() {
     if (this.profiles) {
       let uid = this._uid;
 
       while (uid >= 0) {
         if (this.profiles.has(uid)) {

--- a/browser/devtools/profiler/cleopatra/js/devtools.js
+++ b/browser/devtools/profiler/cleopatra/js/devtools.js
@@ -10,25 +10,29 @@ var gInstanceUID;
  *
  * @param string status
  *   Status to send to the parent page:
  *    - loaded, when page is loaded.
  *    - start, when user wants to start profiling.
  *    - stop, when user wants to stop profiling.
  *    - disabled, when the profiler was disabled
  *    - enabled, when the profiler was enabled
+ *    - displaysource, when user wants to display source
+ * @param object data (optional)
+ *    Additional data to send to the parent page.
  */
-function notifyParent(status) {
+function notifyParent(status, data={}) {
   if (!gInstanceUID) {
     gInstanceUID = window.location.search.substr(1);
   }
 
   window.parent.postMessage({
     uid: gInstanceUID,
-    status: status
+    status: status,
+    data: data
   }, "*");
 }
 
 /**
  * A listener for incoming messages from the parent
  * page. All incoming messages must be stringified
  * JSON objects to be compatible with Cleopatra's
  * format:
@@ -192,17 +196,17 @@ function enterFinishedProfileUI() {
   gPluginView = new PluginView();
   tree.appendChild(gPluginView.getContainer());
 
   gMainArea.appendChild(cover);
   gMainArea.appendChild(pane);
 
   var currentBreadcrumb = gSampleFilters;
   gBreadcrumbTrail.add({
-    title: "Complete Profile",
+    title: gStrings["Complete Profile"],
     enterCallback: function () {
       gSampleFilters = [];
       filtersChanged();
     }
   });
 
   if (currentBreadcrumb == null || currentBreadcrumb.length == 0) {
     gTreeManager.restoreSerializedSelectionSnapshot(gRestoreSelection);

--- a/browser/devtools/profiler/cleopatra/js/tree.js
+++ b/browser/devtools/profiler/cleopatra/js/tree.js
@@ -461,17 +461,18 @@ TreeView.prototype = {
     }
     return '<input type="button" value="Expand / Collapse" class="expandCollapseButton" tabindex="-1"> ' +
       '<span class="sampleCount">' + node.counter + '</span> ' +
       '<span class="samplePercentage">' + samplePercentage + '</span> ' +
       '<span class="selfSampleCount">' + node.selfCounter + '</span> ' +
       '<span class="resourceIcon" data-resource="' + node.library + '"></span> ' +
       '<span class="functionName">' + nodeName + '</span>' +
       '<span class="libraryName">' + libName + '</span>' +
-      '<input type="button" value="Focus Callstack" title="Focus Callstack" class="focusCallstackButton" tabindex="-1">';
+      (nodeName === '(total)' ? '' :
+        '<input type="button" value="Focus Callstack" title="Focus Callstack" class="focusCallstackButton" tabindex="-1">');
   },
   _resolveChildren: function TreeView__resolveChildren(div, childrenCollapsedValue) {
     while (div.pendingExpand != null && div.pendingExpand.length > 0) {
       var pendingExpand = div.pendingExpand.shift();
       pendingExpand.allChildrenCollapsedValue = childrenCollapsedValue;
       this._pendingActions.push(pendingExpand);
       this._schedulePendingActionProcessing();
     }

--- a/browser/devtools/profiler/cleopatra/js/ui.js
+++ b/browser/devtools/profiler/cleopatra/js/ui.js
@@ -164,18 +164,22 @@ function ProfileTreeManager() {
     if (window.comparator_setSelection) {
       window.comparator_setSelection(gTreeManager.serializeCurrentSelectionSnapshot(), frameData);
     }
   });
   this.treeView.addEventListener("contextMenuClick", function (e) {
     self._onContextMenuClick(e);
   });
   this.treeView.addEventListener("focusCallstackButtonClicked", function (frameData) {
-    var focusedCallstack = self._getCallstackUpTo(frameData);
-    focusOnCallstack(focusedCallstack, frameData.name);
+    // NOTE: Not in the original Cleopatra source code.
+    notifyParent("displaysource", {
+      line: frameData.scriptLocation.lineInformation,
+      uri: frameData.scriptLocation.scriptURI,
+      isChrome: /^otherhost_*/.test(frameData.library)
+    });
   });
   this._container = document.createElement("div");
   this._container.className = "tree";
   this._container.appendChild(this.treeView.getContainer());
 
   // If this is set when the tree changes the snapshot is immediately restored.
   this._savedSnapshot = null;
 }
@@ -1561,17 +1565,18 @@ function focusOnSymbol(focusSymbol, name
     enterCallback: function () {
       gSampleFilters = newFilterChain;
       filtersChanged();
     }
   });
 }
 
 function focusOnCallstack(focusedCallstack, name, overwriteCallstack) {
-  var invertCallback =  gInvertCallstack;
+  var invertCallstack = gInvertCallstack;
+
   if (overwriteCallstack != null) {
     invertCallstack = overwriteCallstack;
   }
   var filter = {
     type: !invertCallstack ? "FocusedCallstackPostfixSampleFilter" : "FocusedCallstackPrefixSampleFilter",
     name: name,
     focusedCallstack: focusedCallstack,
     appliesToJS: gJavascriptOnly

--- a/browser/devtools/profiler/test/Makefile.in
+++ b/browser/devtools/profiler/test/Makefile.in
@@ -5,17 +5,26 @@
 DEPTH          = @DEPTH@
 topsrcdir      = @top_srcdir@
 srcdir         = @srcdir@
 VPATH          = @srcdir@
 relativesrcdir = @relativesrcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-MOCHITEST_BROWSER_FILES = \
+MOCHITEST_BROWSER_TESTS = \
 		browser_profiler_run.js \
 		browser_profiler_controller.js \
 		browser_profiler_profiles.js \
 		browser_profiler_remote.js \
 		browser_profiler_bug_830664_multiple_profiles.js \
+		browser_profiler_bug_834878_source_buttons.js \
 		head.js \
+		$(NULL)
+
+MOCHITEST_BROWSER_PAGES = \
+		mock_profiler_bug_834878_page.html \
+		mock_profiler_bug_834878_script.js \
+		$(NULL)
+
+MOCHITEST_BROWSER_FILES_PARTS = MOCHITEST_BROWSER_TESTS MOCHITEST_BROWSER_PAGES
 
 include $(topsrcdir)/config/rules.mk

new file mode 100644
--- /dev/null
+++ b/browser/devtools/profiler/test/browser_profiler_bug_834878_source_buttons.js
@@ -0,0 +1,29 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const BASE = "http://example.com/browser/browser/devtools/profiler/test/";
+const URL = BASE + "mock_profiler_bug_834878_page.html";
+const SCRIPT = BASE + "mock_profiler_bug_834878_script.js";
+
+function test() {
+  waitForExplicitFinish();
+
+  setUp(URL, function onSetUp(tab, browser, panel) {
+    panel.once("profileCreated", function () {
+      let data = { uri: SCRIPT, line: 5, isChrome: false };
+
+      panel.displaySource(data, function onOpen() {
+        let target = TargetFactory.forTab(tab);
+        let dbg = gDevTools.getToolbox(target).getPanel("jsdebugger");
+        let view = dbg.panelWin.DebuggerView;
+
+        is(view.Sources.selectedValue, data.uri, "URI is different");
+        is(view.editor.getCaretPosition().line, data.line - 1, "Line is different");
+
+        tearDown(tab);
+      });
+    });
+
+    panel.createProfile();
+  });
+}

new file mode 100644
--- /dev/null
+++ b/browser/devtools/profiler/test/mock_profiler_bug_834878_page.html
@@ -0,0 +1,14 @@
+<!-- Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/publicdomain/zero/1.0/ -->
+
+<!DOCTYPE HTML>
+<html>
+  <head>
+    <meta charset='utf-8'/>
+    <title>Profiler Script Linking Test</title>
+    <script type="text/javascript" src="mock_profiler_bug_834878_script.js">
+    </script>
+  </head>
+  <body>
+  </body>
+</html>

new file mode 100644
--- /dev/null
+++ b/browser/devtools/profiler/test/mock_profiler_bug_834878_script.js
@@ -0,0 +1,7 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function main() {
+  console.log("Hello, World!");
+  return 0;
+}
\ No newline at end of file

--- a/browser/locales/en-US/chrome/browser/devtools/profiler.properties
+++ b/browser/locales/en-US/chrome/browser/devtools/profiler.properties
@@ -13,17 +13,17 @@
 # LOCALIZATION NOTE (profiler.label):
 # This string is displayed in the title of the tab when the profiler is
 # displayed inside the developer tools window and in the Developer Tools Menu.
 profiler.label=Profiler
 
 # LOCALIZATION NOTE (profiler.commandkey, profiler.accesskey)
 # Used for the menuitem in the tool menu
 profiler.commandkey=Y
-profiler.accesskey=Y
+profiler.accesskey=P
 
 # LOCALIZATION NOTE (profiler.tooltip):
 # This string is displayed in the tooltip of the tab when the profiler is
 # displayed inside the developer tools window.
 profiler.tooltip=Profiler
 
 # LOCALIZATION NOTE (profiler.profileName):
 # This string is the default name for new profiles. Its parameter is a number.

--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -1435,16 +1435,47 @@ nsDOMWindowUtils::GetScrollXY(bool aFlus
 
   *aScrollX = nsPresContext::AppUnitsToIntCSSPixels(scrollPos.x);
   *aScrollY = nsPresContext::AppUnitsToIntCSSPixels(scrollPos.y);
 
   return NS_OK;
 }
 
 NS_IMETHODIMP
+nsDOMWindowUtils::GetScrollbarWidth(bool aFlushLayout, int32_t* aResult)
+{
+  if (!nsContentUtils::IsCallerChrome()) {
+    return NS_ERROR_DOM_SECURITY_ERR;
+  }
+
+  *aResult = 0;
+
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  NS_ENSURE_STATE(window);
+
+  nsCOMPtr<nsIDocument> doc(do_QueryInterface(window->GetExtantDocument()));
+  NS_ENSURE_STATE(doc);
+
+  if (aFlushLayout) {
+    doc->FlushPendingNotifications(Flush_Layout);
+  }
+
+  nsIPresShell* presShell = doc->GetShell();
+  NS_ENSURE_TRUE(presShell, NS_ERROR_NOT_AVAILABLE);
+
+  nsIScrollableFrame* scrollFrame = presShell->GetRootScrollFrameAsScrollable();
+  NS_ENSURE_TRUE(scrollFrame, NS_OK);
+
+  nsMargin sizes = scrollFrame->GetActualScrollbarSizes();
+  *aResult = nsPresContext::AppUnitsToIntCSSPixels(sizes.LeftRight());
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
 nsDOMWindowUtils::GetRootBounds(nsIDOMClientRect** aResult)
 {
   if (!nsContentUtils::IsCallerChrome()) {
     return NS_ERROR_DOM_SECURITY_ERR;
   }
 
   // Weak ref, since we addref it below
   nsClientRect* rect = new nsClientRect();

--- a/dom/interfaces/base/nsIDOMWindowUtils.idl
+++ b/dom/interfaces/base/nsIDOMWindowUtils.idl
@@ -36,17 +36,17 @@ interface nsIDOMWindow;
 interface nsIDOMBlob;
 interface nsIDOMFile;
 interface nsIFile;
 interface nsIDOMTouch;
 interface nsIDOMClientRect;
 interface nsIURI;
 interface nsIDOMEventTarget;
 
-[scriptable, uuid(020deb5a-cba6-41dd-8551-72a880d01970)]
+[scriptable, uuid(16b3bdcc-75d4-11e2-8a20-aaff78957a39)]
 interface nsIDOMWindowUtils : nsISupports {
 
   /**
    * Image animation mode of the window. When this attribute's value
    * is changed, the implementation should set all images in the window
    * to the given value. That is, when set to kDontAnimMode, all images
    * will stop animating. The attribute's value must be one of the
    * animationMode values from imgIContainer.
@@ -643,16 +643,23 @@ interface nsIDOMWindowUtils : nsISupport
    * Returns the scroll position of the window's currently loaded document.
    *
    * @param aFlushLayout flushes layout if true. Otherwise, no flush occurs.
    * @see nsIDOMWindow::scrollX/Y
    */
   void getScrollXY(in boolean aFlushLayout, out long aScrollX, out long aScrollY);
 
   /**
+   * Returns the scrollbar width of the window's scroll frame.
+   *
+   * @param aFlushLayout flushes layout if true. Otherwise, no flush occurs.
+   */
+  long getScrollbarWidth(in boolean aFlushLayout);
+
+  /**
    * Returns the bounds of the window's currently loaded document. This will
    * generally be (0, 0, pageWidth, pageHeight) but in some cases (e.g. RTL
    * documents) may have a negative left value.
    */
   nsIDOMClientRect getRootBounds();
 
   /**
    * Get IME open state. TRUE means 'Open', otherwise, 'Close'.

--- a/dom/tests/mochitest/general/Makefile.in
+++ b/dom/tests/mochitest/general/Makefile.in
@@ -24,16 +24,18 @@ MOCHITEST_FILES = \
 		file_bug628069.html \
 		test_bug631440.html \
 		test_bug653364.html \
 		test_bug629535.html \
 		test_clientRects.html \
 		test_consoleAPI.html \
 		test_domWindowUtils.html \
 		test_domWindowUtils_scrollXY.html \
+		test_domWindowUtils_scrollbarWidth.html \
+		file_domWindowUtils_scrollbarWidth.html \
 		test_offsets.html \
 		test_offsets.js \
 		test_windowProperties.html \
 		test_clipboard_events.html \
 		test_frameElementWrapping.html \
 		file_frameElementWrapping.html \
 		test_framedhistoryframes.html \
 		test_windowedhistoryframes.html \

new file mode 100644
--- /dev/null
+++ b/dom/tests/mochitest/general/file_domWindowUtils_scrollbarWidth.html
@@ -0,0 +1,7 @@
+<!DOCTYPE HTML>
+<html>
+<body style='width: 100000px; overflow: hidden;'></body>
+  <div id="float" style="float: left; overflow: scroll;">
+    <div style="width: 200px;"></div>
+  </div>
+</html>

new file mode 100644
--- /dev/null
+++ b/dom/tests/mochitest/general/test_domWindowUtils_scrollbarWidth.html
@@ -0,0 +1,48 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>nsIDOMWindowUtils::getScrollbarWidth test</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css">
+</head>
+
+<body id="body">
+  <script type="application/javascript;version=1.8">
+    function doTests() {
+      let iframe = document.getElementById("iframe");
+      let cwindow = iframe.contentWindow;
+      let utils = SpecialPowers.getDOMWindowUtils(cwindow);
+      let doc = cwindow.document;
+
+      function haveNonFloatingScrollbars() {
+        return doc.getElementById("float").offsetWidth > 200;
+      }
+
+      is(utils.getScrollbarWidth(true), 0,
+         "getScrollbarWidth returns zero without a scrollbar");
+
+      // Some platforms (esp. mobile) may have floating scrollbars that don't
+      // affect layout. Thus getScrollbarWidth() would always return 0.
+      if (haveNonFloatingScrollbars()) {
+        let body = doc.querySelector("body");
+        body.style.overflowY = "scroll";
+
+        is(utils.getScrollbarWidth(false), 0,
+           "getScrollbarWidth returns zero with a vertical scrollbar w/o flushing");
+
+        ok(utils.getScrollbarWidth(true) > 0,
+           "getScrollbarWidth returns non-zero with a vertical scrollbar with flushing");
+      }
+
+      SimpleTest.finish();
+    }
+
+    SimpleTest.waitForExplicitFinish();
+  </script>
+
+  <iframe src="http://mochi.test:8888/tests/dom/tests/mochitest/general/file_domWindowUtils_scrollbarWidth.html"
+          id="iframe" onload="doTests();">
+  </iframe>
+
+</body>
+</html>