Implement native GMB backbuffers in the GLES2 Command Decoder.

gpu/command_buffer/service/context_group.h

Index: gpu/command_buffer/service/context_group.h
diff --git a/gpu/command_buffer/service/context_group.h b/gpu/command_buffer/service/context_group.h
index 00d74aad007fcafe8f0ad5c92977f31ed5a18861..db0381ead12333e3aa381453cee1cf0dba28ce94 100644
--- a/gpu/command_buffer/service/context_group.h
+++ b/gpu/command_buffer/service/context_group.h
@@ -25,6 +25,7 @@
 
 namespace gpu {
 
+class ImageFactory;
 struct GpuPreferences;
 class TransferBufferManager;
 
@@ -56,7 +57,8 @@ class GPU_EXPORT ContextGroup : public base::RefCounted<ContextGroup> {
       const scoped_refptr<FramebufferCompletenessCache>&
           framebuffer_completeness_cache,
       const scoped_refptr<FeatureInfo>& feature_info,
-      bool bind_generates_resource);
+      bool bind_generates_resource,
+      gpu::ImageFactory* image_factory);
 
   // This should only be called by GLES2Decoder. This must be paired with a
   // call to destroy if it succeeds.
@@ -145,6 +147,8 @@ class GPU_EXPORT ContextGroup : public base::RefCounted<ContextGroup> {
     return feature_info_.get();
   }
 
+  gpu::ImageFactory* image_factory() { return image_factory_; }
+
   const GpuPreferences& gpu_preferences() const {
     return gpu_preferences_;
   }
@@ -276,6 +280,8 @@ class GPU_EXPORT ContextGroup : public base::RefCounted<ContextGroup> {
 
   scoped_refptr<FeatureInfo> feature_info_;
 
+  gpu::ImageFactory* image_factory_;
+
   std::vector<base::WeakPtr<gles2::GLES2Decoder> > decoders_;
 
   // Mappings from client side IDs to service side IDs.