Bug 1338215 - use a windowless browser for thumbnail hosting, r=markh

MozReview-Commit-ID: LWzMDHu0N8H --HG-- extra : rebase_source : faa8b821a46a164d3426f2551fd6f704deef41eb
2017-02-27 19:58:55 +00:00 · 2017-02-27 19:58:55 +00:00 · 375ee5a24a
--- a/toolkit/components/thumbnails/BackgroundPageThumbs.jsm
+++ b/toolkit/components/thumbnails/BackgroundPageThumbs.jsm
@ -160,20 +160,31 @@ const BackgroundPageThumbs = {

    this._startedParentWinInit = true;

-    // Create an html:iframe, stick it in the parent document, and
-    // use it to host the browser.  about:blank will not have the system
-    // principal, so it can't host, but a document with a chrome URI will.
-    let hostWindow = Services.appShell.hiddenDOMWindow;
-    let iframe = hostWindow.document.createElementNS(HTML_NS, "iframe");
-    iframe.setAttribute("src", "chrome://global/content/mozilla.xhtml");
-    let onLoad = function onLoadFn() {
-      iframe.removeEventListener("load", onLoad, true);
-      this._parentWin = iframe.contentWindow;
-      this._processCaptureQueue();
-    }.bind(this);
-    iframe.addEventListener("load", onLoad, true);
-    hostWindow.document.documentElement.appendChild(iframe);
-    this._hostIframe = iframe;
+    // Create a windowless browser and load our hosting
+    // (privileged) document in it.
+    let wlBrowser = Services.appShell.createWindowlessBrowser(true);
+    wlBrowser.QueryInterface(Ci.nsIInterfaceRequestor);
+    let webProgress = wlBrowser.getInterface(Ci.nsIWebProgress);
+    let listener = {
+      QueryInterface: XPCOMUtils.generateQI([
+        Ci.nsIWebProgressListener, Ci.nsIWebProgressListener2,
+        Ci.nsISupportsWeakReference]),
+    };
+    listener.onStateChange = (wbp, request, stateFlags, status) => {
+      if (!request) {
+        return;
+      }
+      if (stateFlags & Ci.nsIWebProgressListener.STATE_STOP &&
+          stateFlags & Ci.nsIWebProgressListener.STATE_IS_NETWORK) {
+        webProgress.removeProgressListener(listener);
+        // Get the window reference via the document.
+        this._parentWin = wlBrowser.document.defaultView;
+        this._processCaptureQueue();
+      }
+    };
+    webProgress.addProgressListener(listener, Ci.nsIWebProgress.NOTIFY_STATE_ALL);
+    wlBrowser.loadURI("chrome://global/content/backgroundPageThumbs.xhtml", 0, null, null, null);
+    this._windowlessContainer = wlBrowser;

    return false;
  },
@ -186,10 +197,10 @@ const BackgroundPageThumbs = {
    if (this._captureQueue)
      this._captureQueue.forEach(cap => cap.destroy());
    this._destroyBrowser();
-    if (this._hostIframe)
-      this._hostIframe.remove();
+    if (this._windowlessContainer)
+      this._windowlessContainer.close();
    delete this._captureQueue;
-    delete this._hostIframe;
+    delete this._windowlessContainer;
    delete this._startedParentWinInit;
    delete this._parentWin;
  },
--- a/toolkit/components/thumbnails/content/backgroundPageThumbs.xhtml
+++ b/toolkit/components/thumbnails/content/backgroundPageThumbs.xhtml
@ -0,0 +1,16 @@
+<!DOCTYPE html>
+
+<!-- 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/. -->
+
+<!-- This page is used to host a (remote) browser for background page
+     thumbnailing purposes. It's always loaded as chrome:// . -->
+<html xmlns="http://www.w3.org/1999/xhtml">
+  <head>
+    <meta charset='utf-8' />
+    <title>backgroundPageThumbs.html</title>
+  </head>
+  <body></body>
+</html>
+
--- a/toolkit/components/thumbnails/content/backgroundPageThumbsContent.js
+++ b/toolkit/components/thumbnails/content/backgroundPageThumbsContent.js
@ -189,6 +189,10 @@ const backgroundPageThumbsContent = {
  // reasons: GC the captured page, and ensure it can't possibly load any more
  // resources.
  _loadAboutBlank: function _loadAboutBlank() {
+    // It's possible we've been destroyed by now, if so don't do anything:
+    if (!docShell) {
+      return;
+    }
    this._webNav.loadURI("about:blank",
                         Ci.nsIWebNavigation.LOAD_FLAGS_STOP_CONTENT,
                         null, null, null);
--- a/toolkit/components/thumbnails/jar.mn
+++ b/toolkit/components/thumbnails/jar.mn
@ -3,4 +3,5 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.

 toolkit.jar:
+  content/global/backgroundPageThumbs.xhtml     (content/backgroundPageThumbs.xhtml)
  content/global/backgroundPageThumbsContent.js (content/backgroundPageThumbsContent.js)