tree 60b5ac6ca4c56f2fb71d03aeb263b04af2d634e8
parent 24e0391654b1f9344b4c6fa357326728e012f533
author sigbjornf@opera.com <sigbjornf@opera.com> 1437723501 +0000
committer sigbjornf@opera.com <sigbjornf@opera.com> 1437723501 +0000

Make ContentDecryptionModuleResult cross-thread destructible.

So as to handle cross-thread uses of the corresponding
WebContentDecryptionModuleResult (WCDMResult), have WCDMResult
keep a cross-thread persistent (CrossThreadPersistent<>) by
way of its WebPrivatePtr<> reference.

CrossThreadPersistent<> can be destructed on a thread other than
the Oilpan thread creating it; the thread does not have to be
attached to Oilpan.

To control if WebPrivatePtr<> should use a cross-thread persistent
or not, it is now parameterized over an enum controlling which.
The default is to use same-thread persistents. If

  WebPrivatePtr<T, AllowCrossThreadDestruction>

is for a ref-counted T, T must derive from ThreadSafeRefCounted<T>. 

R=jrummell,xhwang,haraken,tkent
BUG=509588

Review URL: https://codereview.chromium.org/1249913002

git-svn-id: svn://svn.chromium.org/blink/trunk@199421 bbb929c8-8fbe-4397-9dbb-9b2b20218538