Revert 272540 "Revert 272504 "Destroy all rtc peer connection ha..."

Revert 272540 "Revert 272504 "Destroy all rtc peer connection ha..."

The original change was not a root cause of the problem.
sheriffs are looking into other possible causes.

Meanwhile I am getting the change back in.

> Revert 272504 "Destroy all rtc peer connection handlers before s..."
> 
> On Win7 Tests (dbg)(2) these tests
> 
> FocusElementCallsFocusedNodeChanged
> GetCompositionCharacterBoundsTest
> MessageOrderInDidChangeSelection
> OnExtendSelectionAndDelete
> OnImeTypeChanged
> OnSetTextDirection
> SendCandidateWindowEvents
> SetEditableSelectionAndComposition
> 
> fail with timeout.
> http://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%282%29/builds/21101/steps/content_browsertests/logs/stdio
> 
> > Destroy all rtc peer connection handlers before shutting down blink
> > 
> > The connection handlers will otherwise continue to call into blink which
> > is bound to crash after it was shut down.
> > 
> > BUG=337572
> > R=perkj@chromium.org,adamk@chromium.org
> > 
> > Review URL: https://codereview.chromium.org/292163002
> 
> TBR=jochen@chromium.org
> 
> Review URL: https://codereview.chromium.org/296213007

TBR=vasilii@chromium.org,jochen@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272604

[fgorski, 2014-05-23 22:00:10]

Committed patchset #1 manually as r272604.

[jochen (gone - plz use gerrit), 2014-05-24 10:17:20]

thx for relanding