[Android WebView] Add a quirk to clobber initial scale in certain cases

In the following cases, the viewport meta tag would take precedence over
the value specified in setInitialPageScaleOverride:

The value provided to setInitialPageScaleOverride is <= 1 / device pixel ratio AND

   - viewport meta has width=device-width OR

   - viewport meta has auto width, and the page would be displayed at 100% scale.

BUG=313754

Review URL: https://codereview.chromium.org/55073002

git-svn-id: svn://svn.chromium.org/blink/trunk@161355 bbb929c8-8fbe-4397-9dbb-9b2b20218538