Hook up ui::Compositor to Display's BeginFrameSource

components/mus/surfaces/surfaces_context_provider.h

Index: components/mus/surfaces/surfaces_context_provider.h
diff --git a/components/mus/surfaces/surfaces_context_provider.h b/components/mus/surfaces/surfaces_context_provider.h
index bb3a4c6660d76315cd968fc6c4168acde2ec3667..f7595e6450fff9c8a40298dda760fe7c7adb43be 100644
--- a/components/mus/surfaces/surfaces_context_provider.h
+++ b/components/mus/surfaces/surfaces_context_provider.h
@@ -39,10 +39,11 @@ class SurfacesContextProvider : public cc::ContextProvider,
                                 public CommandBufferLocalClient,
                                 public base::NonThreadSafe {
  public:
-  SurfacesContextProvider(SurfacesContextProviderDelegate* delegate,
-                          gfx::AcceleratedWidget widget,
+  SurfacesContextProvider(gfx::AcceleratedWidget widget,
                           const scoped_refptr<GpuState>& state);
 
+  void SetDelegate(SurfacesContextProviderDelegate* delegate);
+
   // cc::ContextProvider implementation.
   bool BindToCurrentThread() override;
   gpu::gles2::GLES2Interface* ContextGL() override;