Extend MouseWheelEvent to support both X and Y scrolls
The patch extends the ui::MouseWheelEvent class to support
X (horizontal) scrolls and updates the corresponding interface
in event_utils.h. It also revises throughout the codebase where
the old method calls were used.
Contributed by sheckylin@chromium.org
BUG=231419
TEST=Tested on device.
Change-Id: I86a7b6b62ec4ac8c296251a2333234170f1cd2e7
Review URL: https://chromiumcodereview.appspot.com/
13829007
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198086 0039d316-1c4b-4281-b951-d872f2087c98