Plumbing explicit share groups through context creation

content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h

Index: content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
diff --git a/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h b/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
index a50c9d50d8317ff5914f8534c66a73e9f5002b4d..b1b1f59d75c17e0104e64ab34ffb5fa19ae78882 100644
--- a/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
+++ b/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
@@ -108,7 +108,8 @@ class WebGraphicsContext3DCommandBufferImpl
           GpuChannelHost* host,
           const WebGraphicsContext3D::Attributes& attributes,
           const GURL& active_url,
-          const SharedMemoryLimits& limits);
+          const SharedMemoryLimits& limits,
+          WebGraphicsContext3D* share_context);
 
   size_t GetMappedMemoryLimit() {
     return mem_limits_.mapped_memory_reclaim_limit;
@@ -662,9 +663,10 @@ class WebGraphicsContext3DCommandBufferImpl
   // and subsequent calls are ignored. Must be called from the thread that is
   // going to use this object to issue GL commands (which might not be the main
   // thread).
-  bool MaybeInitializeGL();
+  bool MaybeInitializeGL(WebGraphicsContext3DCommandBufferImpl* share_context);
 
-  bool InitializeCommandBuffer(bool onscreen);
+  bool InitializeCommandBuffer(
+      bool onscreen, WebGraphicsContext3DCommandBufferImpl* share_context);
 
   void Destroy();
 
@@ -681,7 +683,8 @@ class WebGraphicsContext3DCommandBufferImpl
   // allocate both fake PluginWindowHandles and NativeViewIds and map
   // from fake NativeViewIds to PluginWindowHandles, but this seems like
   // unnecessary complexity at the moment.
-  bool CreateContext(bool onscreen);
+  bool CreateContext(
+      bool onscreen, WebGraphicsContext3DCommandBufferImpl* share_context);
 
   virtual void OnGpuChannelLost();
   virtual void OnErrorMessage(const std::string& message, int id);
@@ -723,6 +726,8 @@ class WebGraphicsContext3DCommandBufferImpl
   SharedMemoryLimits mem_limits_;
 
   uint32_t flush_id_;
+
+  CommandBufferProxyImpl* share_group_;
 };
 
 }  // namespace content