Merge 143363

Merge 143363
> Update FeatureObserver on top level navigation in addition to page destruction.
> https://bugs.webkit.org/show_bug.cgi?id=109874
> 
> Patch by Kassy Coan <kassycoan@chromium.org>; on 2013-02-19
> Reviewed by Adam Barth.
> 
> No new tests. Only effect is to histogram more frequently.
> 
> * loader/FrameLoader.cpp:
> (WebCore::FrameLoader::dispatchDidCommitLoad):
> * page/FeatureObserver.cpp:
> (WebCore::FeatureObserver::~FeatureObserver):
> (WebCore):
> (WebCore::FeatureObserver::updateMeasurements):
> (WebCore::FeatureObserver::didCommitLoad):
> * page/FeatureObserver.h:
> (FeatureObserver):

TBR=commit-queue@webkit.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=143883