Update from https://crrev.com/316786

cc/output/output_surface.h

Index: cc/output/output_surface.h
diff --git a/cc/output/output_surface.h b/cc/output/output_surface.h
index 29e32a5317ef3c61f2b329f6a390d1eb0d0f115f..3e3b085dcff57109232fbceaa78c11a3b57cf2dd 100644
--- a/cc/output/output_surface.h
+++ b/cc/output/output_surface.h
@@ -46,6 +46,11 @@ class CC_EXPORT OutputSurface {
     DEFAULT_MAX_FRAMES_PENDING = 2
   };
 
+  OutputSurface(const scoped_refptr<ContextProvider>& context_provider,
+                const scoped_refptr<ContextProvider>& worker_context_provider,
+                scoped_ptr<SoftwareOutputDevice> software_device);
+  OutputSurface(const scoped_refptr<ContextProvider>& context_provider,
+                const scoped_refptr<ContextProvider>& worker_context_provider);
   explicit OutputSurface(
       const scoped_refptr<ContextProvider>& context_provider);
 
@@ -94,6 +99,9 @@ class CC_EXPORT OutputSurface {
   // In the event of a lost context, the entire output surface should be
   // recreated.
   ContextProvider* context_provider() const { return context_provider_.get(); }
+  ContextProvider* worker_context_provider() const {
+    return worker_context_provider_.get();
+  }
   SoftwareOutputDevice* software_device() const {
     return software_device_.get();
   }
@@ -149,13 +157,15 @@ class CC_EXPORT OutputSurface {
   // Synchronously initialize context3d and enter hardware mode.
   // This can only supported in threaded compositing mode.
   bool InitializeAndSetContext3d(
-      scoped_refptr<ContextProvider> context_provider);
+      scoped_refptr<ContextProvider> context_provider,
+      scoped_refptr<ContextProvider> worker_context_provider);
   void ReleaseGL();
 
   void PostSwapBuffersComplete();
 
   struct OutputSurface::Capabilities capabilities_;
   scoped_refptr<ContextProvider> context_provider_;
+  scoped_refptr<ContextProvider> worker_context_provider_;
   scoped_ptr<SoftwareOutputDevice> software_device_;
   scoped_ptr<OverlayCandidateValidator> overlay_candidate_validator_;
   gfx::Size surface_size_;