Android: SurfaceTexture-based image transport

This is an interim solution for where the embedder cannot use a command buffer context running on the gpu thread for frontend rendering (i.e. for the browser compositor), for example draw functor/callback based UI drawing.
On Android, sharing GL resources across threads is not a given and SurfaceTexture is therefore the only compatible option.

TBR=jam@chromium.org for .gyp change

BUG=161409

Review URL: https://codereview.chromium.org/11343058

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168332 0039d316-1c4b-4281-b951-d872f2087c98

• content/browser/renderer_host/compositor_impl_android.cc[diff]
• content/browser/renderer_host/compositor_impl_android.h[diff]
• content/browser/renderer_host/image_transport_factory_android.cc[diff]
• content/browser/renderer_host/image_transport_factory_android.h[diff]
• content/browser/renderer_host/render_widget_host_view_android.cc[diff]
• content/browser/renderer_host/render_widget_host_view_android.h[diff]
• content/browser/renderer_host/surface_texture_transport_client_android.cc[Added - diff]
• content/browser/renderer_host/surface_texture_transport_client_android.h[Added - diff]
• content/content_browser.gypi[diff]
• content/public/browser/android/compositor.h[diff]
• ui/gl/gl_context_android.cc[diff]
• ui/gl/gl_surface_android.cc[diff]