Add signalSyncPoint to the WebGraphicsContext3D command buffer impls.
Adds signalSyncPoint() support to our command buffer implementations
of WebGraphicsContext3D. Because we have to use a raw callback pointer
for WebGraphicsContext3D and this is not great, I've added a
SyncPointHelper class that adapts a base::Closure() for use with the
signalSyncPoint() method.
Tests:
GLRendererPixelTest.SignalSyncPoint
GLRendererPixelTest.SignalSyncPointOnLostContext
R=jamesr, piman
BUG=179896
Review URL: https://chromiumcodereview.appspot.com/
14126014
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@196930 0039d316-1c4b-4281-b951-d872f2087c98