Issue 2217 - Adapt for content scripts running in about:blank frames

include.preload.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 52 matching lines @@
           // <input type="image"> elements try to load their image again
           // when the "display" CSS property is set. So we have to check
           // that it isn't already collapsed to avoid an infinite recursion.
           if (element.style.getPropertyValue(property) != value ||
               element.style.getPropertyPriority(property) != "important")
             element.style.setProperty(property, value, "important");
         }
       }
     );
   }
+
+  window.collapsing = true;
 }
 
 function checkSitekey()
 {
   var attr = document.documentElement.getAttribute("data-adblockkey");
   if (attr)
     ext.backgroundPage.sendMessage({type: "add-sitekey", token: attr});
 }
 
-function isFrameWithoutContentScript(element)
+function getContentDocument(element)
 {
-  var contentDocument;
   try
   {
-    contentDocument = element.contentDocument;
+    return element.contentDocument;
   }
   catch (e)
   {
-    // This is a third-party frame. Hence we can't access it.
-    // But that's fine, our content script should already run there.
-    return false;
+    return null;
   }
-
-  // The element isn't a <frame>, <iframe> or <object> with "data" attribute.
-  if (!contentDocument)
-    return false;
-
-  // Return true, if the element is a first-party frame which doesn't
-  // have this function, hence our content script isn't running there.
-  // Those are dynamically created frames as well as frames
-  // with "about:blank", "about:srcdoc" and "javascript:" URL.
-  return !("isFrameWithoutContentScript" in contentDocument.defaultView);
 }
 
 function reinjectRulesWhenRemoved(document, style)
 {
   var MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
   if (!MutationObserver)
     return;
 
   var observer = new MutationObserver(function(mutations)
   {
@@ skipping 149 matching lines @@
     checkCollapse(event.target);
   }, true);
 
   document.addEventListener("load", function(event)
   {
     var element = event.target;
 
     if (/^i?frame$/.test(element.localName))
       checkCollapse(element);
 
-    // prior to Chrome 37, content scripts cannot run on about:blank,
-    // about:srcdoc and javascript: URLs. Moreover, as of Chrome 40
-    // "load" and "error" events aren't dispatched there. So we have
-    // to apply element hiding and collapsing from the parent frame.
-    if (/\bChrome\//.test(navigator.userAgent) && isFrameWithoutContentScript(element))
+    if (/\bChrome\//.test(navigator.userAgent))
     {
-      init(element.contentDocument);
+      var contentDocument = getContentDocument(element);
+      if (contentDocument)
+      {
+        var contentWindow = contentDocument.defaultView;
+        if (contentDocument instanceof contentWindow.HTMLDocument)

[kzar, 2015/03/26 12:07:57]

Perhaps we should check that contentWindow isn't null first? According to the
MDN it's possible
https://developer.mozilla.org/en-US/docs/Web/API/Document/defaultView

[Sebastian Noack, 2015/03/26 13:41:19]

I think we can assume frames having a document, also having window (we also did
before). AFAIK, the only case where a document won't have a window is when you
manually create it, e.g. with document.implementation.createDocument().

+        {
+          // Prior to Chrome 37, content scripts cannot run in
+          // dynamically created frames. Also on Chrome 37-40
+          // document_start content scripts (like this one) don't
+          // run either in those frames due to https://crbug.com/416907.
+          // So we have to apply element hiding from the parent frame.
+          if (!("init" in contentWindow))
+            init(contentDocument);
 
-      for (var tagName in typeMap)
-        Array.prototype.forEach.call(element.contentDocument.getElementsByTagName(tagName), checkCollapse);
+          // Moreover, "load" and "error" events aren't dispatched for elements
+          // in dynamically created frames due to https://crbug.com/442107.
+          // So we also have to apply element collpasing from the parent frame.
+          if (!contentWindow.collapsing)
+            [].forEach.call(contentDocument.querySelectorAll(Object.keys(typeMap).join(",")), checkCollapse);

[kzar, 2015/03/26 12:07:57]

Couldn't we put this forEach loop under the above `if (!("init" in
contentWindow))` clause? I don't understand what assigning and checking the
collapsing variable adds over just checking that the init function exists. I'm
probably missing something.

[Sebastian Noack, 2015/03/26 13:41:19]

We are dealing two different issues here:

1. The content script isn't running in the frame. Hence we have to manually
initialize element hiding there.

2. The frame doesn't dispatch load/error events for its elements. So we have to
check for all elements in the loaded frame to potentially collapse them. This
Chrome bug isn't fixed yet, and occurs also for frames running our content
scripts. Therfore this workaround must be performed regardless of the one above.

[kzar, 2015/03/26 14:14:58]

OK, thanks for explaining.

+        }
+      }
     }
   }, true);
 
   return updateStylesheet;
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   window.updateStylesheet = init(document);
 }