Merge 142565

Merge 142565
> [V8] ScheduledAction::m_context can be empty, so we shouldn't
> retrieve an Isolate by using m_context->GetIsolate()
> https://bugs.webkit.org/show_bug.cgi?id=109523
> 
> Reviewed by Adam Barth.
> 
> Chromium bug: https://code.google.com/p/chromium/issues/detail?id=175307#makechanges
> 
> Currently ScheduledAction is retrieving an Isolate by using m_context->GetIsolate().
> This can crash because ScheduledAction::m_context can be empty. Specifically,
> ScheduledAction::m_context is set to ScriptController::currentWorldContext(),
> which can return an empty handle when a frame does not exist. In addition,
> 'if(context.IsEmpty())' in ScheduledAction.cpp implies that it can be empty.
> 
> Alternately, we should pass an Isolate explicitly when a ScheduledAction is instantiated.
> 
> No tests. The Chromium crash report doesn't provide enough information
> to reproduce the bug.
> 
> * bindings/v8/ScheduledAction.cpp:
> (WebCore::ScheduledAction::ScheduledAction):
> (WebCore):
> (WebCore::ScheduledAction::~ScheduledAction):
> * bindings/v8/ScheduledAction.h:
> (ScheduledAction):
> * bindings/v8/custom/V8DOMWindowCustom.cpp:
> (WebCore::WindowSetTimeoutImpl):
> * bindings/v8/custom/V8WorkerContextCustom.cpp:
> (WebCore::SetTimeoutOrInterval):
> 

TBR=haraken@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=142624