Use C OpenGL interface in mojo::GLContext

Use C OpenGL interface in mojo::GLContext

This uses C entry points in mojo::GLContext, used by ganesh_app and
keyboard_native, thus removing the last user of the C++ GL context. I
will remove the SDK entry point for downcast in a follow up once all
downstream consumers have stopped using it. This patch also up the
CHROMIUM_map_sub bindings and fixes up the EXT_debug_marker bindings.

R=viettrungluu@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/fe8fa530e5b9e36adbf3648f9411e59ac26d1e13

[jamesr, 2015-08-24 17:42:36]

jamesr@chromium.org changed reviewers:
+ viettrungluu@chromium.org

[jamesr, 2015-08-24 17:42:36]

Also we need to start autogenerating these thunks files, they're 100% mechanical
except for typos in include guards and inconsistent names

[viettrungluu, 2015-08-24 17:51:06]

LGTM w/(optional) nit. (Ideally, you'd have green-ish trybots too, but you break
it you buy it.)

https://codereview.chromium.org/1307883004/diff/40001/mojo/gpu/gl_context.cc
File mojo/gpu/gl_context.cc (right):

https://codereview.chromium.org/1307883004/diff/40001/mojo/gpu/gl_context.cc#...
mojo/gpu/gl_context.cc:48: return gl_impl_.get();
It should be OK to inline this.

[jamesr, 2015-08-24 17:57:27]

On 2015/08/24 at 17:51:06, viettrungluu wrote:
> LGTM w/(optional) nit. (Ideally, you'd have green-ish trybots too, but you
break it you buy it.)
> 
> https://codereview.chromium.org/1307883004/diff/40001/mojo/gpu/gl_context.cc
> File mojo/gpu/gl_context.cc (right):
> 
>
https://codereview.chromium.org/1307883004/diff/40001/mojo/gpu/gl_context.cc#...
> mojo/gpu/gl_context.cc:48: return gl_impl_.get();
> It should be OK to inline this.

I avoided inlining this to avoid needing to #include the autogen header from the
gl_context.h header (so it can see the is-a relationship between gl_impl_ and
::gpu::GLES2Interface).

[jamesr, 2015-08-24 18:08:19]

On 2015/08/24 at 17:51:06, viettrungluu wrote:
> LGTM w/(optional) nit. (Ideally, you'd have green-ish trybots too, but you
break it you buy it.)

The latest run is green except for Linux (dbg) which is timing out in the go
tests.  The first runs failed as they ran without a prerequisite patch

[jamesr, 2015-08-24 18:10:26]

Committed patchset #3 (id:40001) manually as
fe8fa530e5b9e36adbf3648f9411e59ac26d1e13 (presubmit successful).