Fix DelegatedOutputSurface in Blimp

blimp/client/core/compositor/delegated_output_surface.h

Index: blimp/client/core/compositor/delegated_output_surface.h
diff --git a/blimp/client/core/compositor/delegated_output_surface.h b/blimp/client/core/compositor/delegated_output_surface.h
index 80abddf9810633b0691167d88341eb5cefa12a0a..0482a65386f5d2514ab17322be1ebf8695d130b1 100644
--- a/blimp/client/core/compositor/delegated_output_surface.h
+++ b/blimp/client/core/compositor/delegated_output_surface.h
@@ -5,6 +5,8 @@
 #ifndef BLIMP_CLIENT_CORE_COMPOSITOR_DELEGATED_OUTPUT_SURFACE_H_
 #define BLIMP_CLIENT_CORE_COMPOSITOR_DELEGATED_OUTPUT_SURFACE_H_
 
+#include <memory>
+
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "blimp/client/core/compositor/blimp_output_surface.h"
@@ -15,6 +17,7 @@ class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace cc {
+class BeginFrameSource;
 class ContextProvider;
 }  // namespace cc
 
@@ -50,6 +53,11 @@ class DelegatedOutputSurface : public cc::OutputSurface,
 
   bool bound_to_client_;
 
+  // This OutputSurface is responsible for providing the BeginFrameSource to
+  // drive frame creation.  This will be built on the compositor impl thread at
+  // BindToClient call time.
+  std::unique_ptr<cc::BeginFrameSource> begin_frame_source_;
+
   base::WeakPtrFactory<DelegatedOutputSurface> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DelegatedOutputSurface);