Using the measureSpec from the onMeasure callback to decide whether to set a
fixed layout size or not has proven to be a bit unpredictable. Changing the
code to look at the LayoutParams instead.
BUG=None
TEST=AndroidWebViewTest
// android_webview-only, trybots were happy.
NOTRY=true
Review URL: https://codereview.chromium.org/35403002
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231815 0039d316-1c4b-4281-b951-d872f2087c98