content: Add public context creation API.

content/public/browser/android/compositor.h

Index: content/public/browser/android/compositor.h
diff --git a/content/public/browser/android/compositor.h b/content/public/browser/android/compositor.h
index be022bc50498cf7faed970b281280fb86e3ddf1a..79eaefce7a255911717260c90d93394494cd4974 100644
--- a/content/public/browser/android/compositor.h
+++ b/content/public/browser/android/compositor.h
@@ -22,6 +22,10 @@ class ResourceManager;
 class UIResourceProvider;
 }
 
+namespace gpu {
+class GpuChannelEstablishFactory;
+}
+
 namespace content {
 class CompositorClient;
 
@@ -34,6 +38,8 @@ class CONTENT_EXPORT Compositor {
   // instance can be used. This should be called only once.
   static void Initialize();
 
+  static gpu::GpuChannelEstablishFactory* GetGpuChannelFactory();

[klausw, 2017/03/05 01:49:54]

Should this get a brief comment how it should or should not be used? For
example, it's probably not a good idea to use this context for drawing to the
same surface the compositor is trying to use.

[Khushal, 2017/03/05 01:59:53]

Added a comment. And I think its in general understood that when the compositor
is provided with a surface, no one else should be drawing to it.

+
   // Creates and returns a compositor instance.  |root_window| needs to outlive
   // the compositor as it manages callbacks on the compositor.
   static Compositor* Create(CompositorClient* client,