[Android WebView] Stabilize AwZoomTest.testMagnification...
The page that is used for testing is updated to have wide content, so
Blink actually sets up the page scale to the specified 'initial-scale'.
After loading the page, the test now waits until the page scale becomes
equal to the one specified in 'initial-scale' / 'minimum-scale', which ensures
that the viewport meta tag has been fully processed. This should prevent
the situation when the test discovers that the page can still be zoomed out.
I have encountered an issue with DCHECKs in
InProcessViewRenderer::SetTotalRootLayerScrollOffset, and had to disable
them.
BUG=340327,340648
R=mkosiba@chromium.org
Review URL: https://codereview.chromium.org/
143683005
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249336 0039d316-1c4b-4281-b951-d872f2087c98