For the sheriffs:
Preliminary WebGL support is now being compiled into Chrome; see
http://crbug.com/21852 and http://codereview.chromium.org/270003 . The spec
is still evolving, and there's a higher-than-average chance that upstream
WebKit changes might break the build. If you see any build failures related
to GraphicsContext3D, Canvas*Array, etc. during a WebKit roll, please don't
hesitate to turn ENABLE_3D_CANVAS back to 0
in src/build/features_override.gypi, and I'll fix it.

-Ken