Make earth more responsive to touch
BUG=none
TEST=manually tested on pixel touch screen
R=binji@chromium.org

Review URL: https://codereview.chromium.org/26023007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227137 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227137