Early-return in RenderViewImpl::DidFlushPaint() if there is no WebView.
Early-return in RenderViewImpl::DidFlushPaint() if there is no WebView.

CL 9328016 exposed a bug with seemingly-unused stats code assuming that the RenderView's WebView must be valid when DidFlushPaint() is called, which may not be true if RenderWidget::OnSwapBuffersComplete is notified while the widget is closing down.

We'll follow up by verifying the stats code is unnecessary and removing it (see bug 112942).

BUG=112921,111639,112942


Review URL: http://codereview.chromium.org/9349004

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@120715 0039d316-1c4b-4281-b951-d872f2087c98

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