[tbb-bugs] #14205 [Tor Browser]: Closely review all uses of IsCallerChrome() for e10s

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#14205: Closely review all uses of IsCallerChrome() for e10s
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 Reporter:  mikeperry                            |          Owner:  tbb-
     Type:  task                                 |  team
 Priority:  major                                |         Status:  new
Component:  Tor Browser                          |      Milestone:
 Keywords:  tbb-fingerprinting, tbb-e10s, tbb-   |        Version:
  rebase, ff38-esr                               |  Actual Points:
Parent ID:                                       |         Points:
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 A lot of our fingerprinting patches depend upon the accuracy is
 nsContentUtils::IsCallerChrome() to determine if it is content window or
 browser chrome accessing fingerprinting information.

 IsCallerChrome() kind of scares me, and has had issues for unexpected
 contexts like WebWorkers (See #13027).

 We should keep a close eye on this as we transition to e10s support post
 FF38, as who knows that the child/parent context relationship changes may
 do to various codepaths.

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/14205>
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