Connect GpuVideoDecodeServiceHost with ggl::Context and CommandBufferProxy

BUG=53714

A GpuVideoDecodeServiceHost needs to be connected with a ggl::Contect and its
associated comand buffer for the following reasons:

1. The gpu video decoder in gpu process needs to be in the correct GLES2 context.
2. On context lost the gpu video decoder needs to destroy itself.

This patch is able to connect the GpuVideoDecoderHost to the context although
the context is not passed into the decoder, so the code path is currently broken.

In a future patch we need to do the following:
1. Inject a ggl::Context into IpcVideoDecoder.
2. Complete the plumbing so that inside the gpu process we can associate a
   video decoder with a GLES2 context.

Review URL: http://codereview.chromium.org/3215008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@58517 0039d316-1c4b-4281-b951-d872f2087c98
8 files changed