Remove unused entry point rateLimitOffscreenContextCHROMIUM from WebGraphicsContext3D

BUG=531659

Review URL: https://codereview.chromium.org/1352653002

git-svn-id: svn://svn.chromium.org/blink/trunk/public@202585 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed