[tor-bugs] #13439 [Tor Browser]: Inspector raises the canvas prompt when hovering over images

[Tor Bug Tracker & Wiki]

#13439: Inspector raises the canvas prompt when hovering over images
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     Reporter:  dcf      |      Owner:  tbb-team
         Type:  defect   |     Status:  needs_review
     Priority:  minor    |  Milestone:
    Component:  Tor      |    Version:
  Browser                |   Keywords:  tbb-easy, tbb-usability,
   Resolution:           |  TorBrowserTeam201412R
Actual Points:           |  Parent ID:
       Points:           |
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Comment (by gacar):

 Replying to [comment:15 gk]:
 > gacar: thanks. One question: Why do you have
 > {{{
 > JS::DescribeScriptedCaller(aCx, &scriptFile, &scriptLine)
 > }}}
 > wrapped in an if-clause? Reading the code this means to me this call can
 fail but *not* for
 > third-party content as you are assuming `scriptFile.get()` and
 `scriptLine` are available unconditionally in this scenario. If that is
 correct which failing scenarios did you have in mind?
 I didn't think about any specific scenario but just tried to be cautious.

 When `DescribeScriptedCaller` returns false, we're sure that neither
 `scriptFile` nor `scriptLine` is updated with the caller script's URL and
 line no: http://mxr.mozilla.org/mozilla-esr31/source/js/src/jsapi.cpp#6259

 So there was no reason to continue with the `strcmp`, when `scriptFile`
 doesn't hold the real script URL.

 Does that make sense?

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/13439#comment:16>
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