Pipe SwapBuffers call{,backs} through ContextSupport

This plumbs the SwapBuffers calls and callbacks through the
gpu::ContextSupport interface instead of WGC3D. There are two production
paths for the callbacks - using Echo and using View IPCs. The former is
used everywhere except for single-threaded mac and guest plugin mode.
This implements the Echo path directly in GLES2Implementation and leaves
the implementation of the non-Echo path in WGC3DCommandBufferImpl. We'll
still have to clean that up to avoid having to allocate a WGC3D, but this
at least gets rid of the API dependencies from cc.

R=piman
BUG=181120

Review URL: https://codereview.chromium.org/59233007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239685 0039d316-1c4b-4281-b951-d872f2087c98
Enable spoken feedback on input method change for accessibility.

With this patch, when you change the input method (ctrl-space), spoken feedback notifies the changed input method (e.g. "US, alert").


BUG=271228

Review URL: https://codereview.chromium.org/79183003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239686 0039d316-1c4b-4281-b951-d872f2087c98
Mojo: Array operator[] for handles.

As part of this CL, Array bits are moved out into separate "array"-prefix files.

R=viettrungluu@chromium.org

Review URL: https://codereview.chromium.org/107423003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239687 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239687