Inform webkit when PPAPI plugin contents are opaque.

content/renderer/pepper/pepper_platform_context_3d_impl.h

Index: content/renderer/pepper/pepper_platform_context_3d_impl.h
diff --git a/content/renderer/pepper/pepper_platform_context_3d_impl.h b/content/renderer/pepper/pepper_platform_context_3d_impl.h
index 627d0dce3797211937370806db3709d6ecb014f9..4f5112c191470c466152208ad2618af7d3ca4356 100644
--- a/content/renderer/pepper/pepper_platform_context_3d_impl.h
+++ b/content/renderer/pepper/pepper_platform_context_3d_impl.h
@@ -33,6 +33,7 @@ class PlatformContext3DImpl
 
   virtual bool Init(const int32* attrib_list) OVERRIDE;
   virtual unsigned GetBackingTextureId() OVERRIDE;
+  virtual bool IsOpaque() OVERRIDE;
   virtual gpu::CommandBuffer* GetCommandBuffer() OVERRIDE;
   virtual int GetCommandBufferRouteId() OVERRIDE;
   virtual void SetContextLostCallback(const base::Closure& callback) OVERRIDE;
@@ -47,6 +48,7 @@ class PlatformContext3DImpl
   base::WeakPtr<ContentGLContext> parent_context_;
   scoped_refptr<GpuChannelHost> channel_;
   unsigned int parent_texture_id_;
+  bool has_alpha_;
   CommandBufferProxy* command_buffer_;
   base::Closure context_lost_callback_;
   base::WeakPtrFactory<PlatformContext3DImpl> weak_ptr_factory_;