Disable GPU features AcceleratingCompositing and WebGL by default.

Flags have been switched to reversed logic, and about_flags.cc modified to expose these to users in GUI.

BUG=56053, 59092
TEST=Use about:flags to toggle features, confirm state with e.g. http://webglsamples.googlecode.com/hg/aquarium/aquarium.html http://webkit.org/blog-files/3d-transforms/poster-circle.html Vince's change for about:flags.

Review URL: http://codereview.chromium.org/3978002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@63535 0039d316-1c4b-4281-b951-d872f2087c98
10 files changed