Don't timeout touch event if page scale is fixed

Fixed scale pages are normally mobile-device optimized. Most of them
handle touch events in JavaScript and preventDefault. Don't timeout
touch events for these pages.

BUG=260732,291305

Review URL: https://codereview.chromium.org/26470008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228765 0039d316-1c4b-4281-b951-d872f2087c98
Telemetry: Remove rAF-based fallback for scroll action.

The smoothness measurement, which is the only one using the scroll action, is
only used for Chrome. Chrome always provides some synthetic scrolling support,
so we don't need the fallback option any more.

This patch also checks if synthetic gestures (currently scroll and pinch) are supported by the browser and raises an error if that's not the case.

BUG=305347

Review URL: https://codereview.chromium.org/26877002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228766 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228765
Adding threaded, impl-side painted LayerTreePerfTests

Review URL: https://codereview.chromium.org/27036005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228767 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228767