telemetry: Add more smoothness benchmarks with gpu rasterization.

Adding smoothness benchmarks with GPU rasterization enabled for top_25 and
key_mobile_sites. Planning to run those on the Android perf bots, but without
monitoring for now. Removed smoothness key_silk_cases with explicitly disabled
gpu rasterization, because we are not using it.

R=nduca@chromium.org,tonyg@chromium.org
NOTRY=True
BUG=

Review URL: https://codereview.chromium.org/172953004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252324 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252324
Enable drawingbuffer-test.html on mac amd and android

I think the failure is fixed by blink r167432, which is already rolled into chromium.

BUG=303915
TEST=gpu bots, drawingbuffer-test.html
TBR=kbr@chromium.org

Review URL: https://codereview.chromium.org/174093002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252325 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252325