Construct frame hierarchy using first request originating from it

The initial idea was to fall back to the parent frame when the current frame is not inside the frame hierarchy.

The approach in this review, however, tries to add missing frames to the hierarchy to avoid it alltogether. It does that by adding a frame when the first request that is referencing it is being made.

[Wladimir Palant, 2013-11-06 15:23:13]

http://codereview.adblockplus.org/28067007/diff/1/webrequest.js
File webrequest.js (right):

http://codereview.adblockplus.org/28067007/diff/1/webrequest.js#newcode70
webrequest.js:70: recordFrame(details.tabId, details.frameId,
details.parentFrameId, isFrame ? details.url : null);
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
}

[Thomas Greiner, 2013-11-13 11:52:42]

No objections

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

LGTM with the nit addressed.

http://codereview.adblockplus.org/28067007/diff/5629499534213120/webrequest.js
File webrequest.js (right):

http://codereview.adblockplus.org/28067007/diff/5629499534213120/webrequest.j...
webrequest.js:155: if (tabId in frames && parentFrameId in frames[tabId])
No point for the |tabId in frames| part of the check - it is already known to be
there (see if block above).