Revert 167276 "Remove isolatedWorldForEnteredContext() and isola..."

Revert 167276 "Remove isolatedWorldForEnteredContext() and isola..."

> Remove isolatedWorldForEnteredContext() and isolatedWorldForIsolate()
> 
> - isolatedWorldForIsolate() is equivalent to DOMWrapperWorld::current()->isIsolatedWorld().
> 
> - isolatedWorldForEnteredContext() is equivalent to DOMWrapperWorld::current()->isIsolatedWorld(). Remember that the world of the current context is equal to the world of the entered context.
> 
> Thus this CL replaces these methods with DOMWrapperWorld::current()->isIsolatedWorld().
> 
> BUG=341032
> R=dcarney@chromium.org, eseidel@chromium.org
> 
> Review URL: https://codereview.chromium.org/137953010

TBR=haraken@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=167360

[alecflett, 2014-02-18 20:55:48]

The CQ bit was checked by alecflett@chromium.org

[alecflett, 2014-02-18 20:57:53]

Even after r267289, we're still seeing crashes on Win7 (dbg):
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win7%20(dbg)/bu...

[alecflett, 2014-02-18 21:22:37]

Committed patchset #1 manually as r167360.