Construct frame hierarchy using first request originating from it

webrequest.js

 /*
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  *
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@@ skipping 47 matching lines @@
     return {};
 
   var type = details.type;
 
   // Assume that the first request belongs to the top frame. Chrome may give the
   // top frame the type "object" instead of "main_frame".
   // https://code.google.com/p/chromium/issues/detail?id=281711
   if (details.frameId == 0 && !(details.tabId in frames) && type == "object")
     type = "main_frame";
 
-  var isFrame = (type == "main_frame" || type == "sub_frame");
-  if (!(details.tabId in frames && details.frameId in frames[details.tabId]))
-    recordFrame(details.tabId, details.frameId, details.parentFrameId, isFrame ? details.url : null);

[Wladimir Palant, 2013/11/06 15:23:14]

Frame URLs can change - a different URL can load into the same frame. So we
should *always* call recordFrame() for main_frame and sub_frame requests. Also,
the URL of your newly added frame should be inherited from the parent frame
(that's what our Firefox version does from about:blank anda data: frames),
setting it to the request made is wrong.

So I would actually keep the original code here and add an else clause:

else if (details.tabId in frames && !(details.frameId in frames[details.tabId]))
  recordFrame(details.tabId, details.frameId, details.parentFrameId, null);

And in recordFrame(), instead of your change:

if (frameUrl == null)
{
  if (tabId in frames && parentFrameId in frames[tabId])
    frameUrl = frames[tabId][parentFrameId].url;
  else
    return;  // We cannot do anything meaningful here
}

+  if (type == "main_frame" || type == "sub_frame")
+    recordFrame(details.tabId, details.frameId, details.parentFrameId, details.url);
+  else if (details.tabId in frames && !(details.frameId in frames[details.tabId]))
+    recordFrame(details.tabId, details.frameId, details.parentFrameId, null);
 
   if (type == "main_frame")
     return {};
 
   // Type names match Mozilla's with main_frame and sub_frame being the only exceptions.
   if (type == "sub_frame")
     type = "SUBDOCUMENT";
   else
     type = type.toUpperCase();
 
@@ skipping 60 matching lines @@
     ];
     if (verifySignature(key, signature, params.join("\0")))
       frames[details.tabId][details.frameId].keyException = true;
   }
 }
 
 function recordFrame(tabId, frameId, parentFrameId, frameUrl)
 {
   if (!(tabId in frames))
     frames[tabId] = {};
-  else if (!(frameId in frames[tabId]))
-    frames[tabId][frameId] = {url: frameUrl, parent: parentFrameId};
+
+  if (frameUrl == null)
+  {
+    if (tabId in frames && parentFrameId in frames[tabId])

[Wladimir Palant, 2013/11/13 12:03:03]

No point for the |tabId in frames| part of the check - it is already known to be
there (see if block above).

+      frameUrl = frames[tabId][parentFrameId].url;
+    else
+      return;  // We cannot do anything meaningful here
+  }
+
+  frames[tabId][frameId] = {url: frameUrl, parent: parentFrameId};
 }
 
 function getFrameData(tabId, frameId)
 {
   if (tabId in frames && frameId in frames[tabId])
     return frames[tabId][frameId];
   else if (frameId > 0 && tabId in frames && 0 in frames[tabId])
   {
     // We don't know anything about javascript: or data: frames, use top frame
     return frames[tabId][0];
@@ skipping 39 matching lines @@
     parent = frameData.parent;
     parentData = getFrameData(tabId, parent);
 
     var frameUrl = frameData.url;
     var parentUrl = (parentData ? parentData.url : frameUrl);
     if ("keyException" in frameData || isWhitelisted(frameUrl, parentUrl, type))
       return true;
   }
   return false;
 }