Revert of gpu: support GL_TEXTURE_CUBE_MAP destination target to Copy(Sub)TextureCHROMIUM. (patchset #10 id:200001 of https://codereview.chromium.org/1275773003/ )

Reason for revert:
Linux AMD GPU FYI bot has a broken gl_tests, likely because of this patch.

http://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/41273

[ RUN      ] GLCopyTextureCHROMIUMTests/GLCopyTextureCHROMIUMTest.Basic/2
Received signal 11 SEGV_MAPERR 000000000045
#0 0x000000492795 base::debug::(anonymous namespace)::StackDumpSignalHandler()
#1 0x7ff52630acb0 <unknown>
#2 0x7ff5232a858c <unknown>
#3 0x7ff5230a247c <unknown>
#4 0x7ff5230a33ae <unknown>
#5 0x7ff5227e8585 <unknown>
#6 0x7ff5227e9b0a <unknown>
#7 0x7ff522bf75c3 <unknown>
#8 0x0000004f7ba4 gfx::GLApiBase::glCopyTexImage2DFn()
#9 0x000000596ac1 (anonymous namespace)::DoCopyTexImage2D()
#10 0x0000005968c4 gpu::CopyTextureCHROMIUMResourceManager::DoCopyTexture()

Original issue's description:
> gpu: support GL_TEXTURE_CUBE_MAP destination target to Copy(Sub)TextureCHROMIUM.
>
> It makes it possible to optimize WebGL.
>
> TEST=gl_tests GLCopyTextureCHROMIUMTests/GLCopyTextureCHROMIUMTest.*
> BUG=517548
>
> Committed: https://crrev.com/fa25f0e5786527e63c6ff9aeda77da3bd7456ee3
> Cr-Commit-Position: refs/heads/master@{#347354}

TBR=piman@chromium.org,sievers@chromium.org,kbr@chromium.org,zmo@chromium.org,dongseong.hwang@intel.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=517548,528374

Review URL: https://codereview.chromium.org/1304103005

Cr-Commit-Position: refs/heads/master@{#347465}
9 files changed