Revert of Re-land: ui: Move GLImage::BindTexImage fallback from GLImage implementations to GLES2CmdDecoder.

Revert of Re-land: ui: Move GLImage::BindTexImage fallback from GLImage implementations to GLES2CmdDecoder. (patchset #16 id:300001 of https://codereview.chromium.org/1401423003/ )

Reason for revert:
Unfortunately Android gpu bots still fail
https://build.chromium.org/p/chromium.gpu/builders/Android%20Debug%20%28Nexus%209%29/builds/3332/steps/webgl_conformance_tests/logs/stdio

Original issue's description:
> Re-land: ui: Move GLImage::BindTexImage fallback from GLImage implementations to GLES2CmdDecoder.
>
> This allows the GPU service to properly track the memory usage
> image backed textures.
>
> It also reduces the complexity of GLImage implementations
> significantly and makes it easier to support format and
> buffer types that require a copy or conversion of data to
> be used for sampling.
>
> This change also includes a few minor GLImage cleanups such
> as removing gfx:: namespace prefix in places where it's not
> needed and making the CopyTexImage GLImage test not part of
> the core GLImage tests as it's optional to support that
> function.
>
> BUG=526298
> TEST=gl_tests --gtest_filter=GpuMemoryBuffer*, gpu_unittests, gl_unittests --gtest_filter=GLImage*
>
> Committed: https://crrev.com/779bd9550a06358ff068edc7458fc8b7b0a69147
> Cr-Commit-Position: refs/heads/master@{#354972}

TBR=dcastagna@chromium.org,ericrk@chromium.org,fsamuel@chromium.org,liberato@chromium.org,sievers@chromium.org,reveman@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=526298
Committed: https://crrev.com/c3342b0fff662d17ff742ab6445a576c98f22bff
Cr-Commit-Position: refs/heads/master@{#355013}

[vasilii, 2015-10-20 08:48:24]

Created Revert of Re-land: ui: Move GLImage::BindTexImage fallback from GLImage
implementations to GLES2CmdDecoder.