Ported GpuCrashTest to Telemetry, renaming the test to ContextLost.

Added command line argument for disabling the WebGL infobar, required
for automated recovery from context loss. Added browser-side handling
of debug URLs for navigations coming from Telemetry, covered under
existing --enable-gpu-benchmarking command line argument.

BUG=308675
R=dtu@chromium.org, jam@chromium.org, zmo@chromium.org

Review URL: https://codereview.chromium.org/27603004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229255 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229255
Add more logging to feedback.
Add some more logging to feedback to diagnose crbug.com/284662

R=xiyuan@chromium.org
BUG=284662

Review URL: https://codereview.chromium.org/27751003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229256 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229256