Convert offscreen canvas to use FrameSinkManagerHost.

content/browser/compositor/gpu_process_transport_factory.h

Index: content/browser/compositor/gpu_process_transport_factory.h
diff --git a/content/browser/compositor/gpu_process_transport_factory.h b/content/browser/compositor/gpu_process_transport_factory.h
index cab105ae0fde582a57c0933fb4bad4ad358912bc..b3a0f651920354fa745978af9e99ec0cfdd5d177 100644
--- a/content/browser/compositor/gpu_process_transport_factory.h
+++ b/content/browser/compositor/gpu_process_transport_factory.h
@@ -16,6 +16,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "build/build_config.h"
+#include "cc/ipc/display_compositor.mojom.h"
 #include "cc/surfaces/frame_sink_id_allocator.h"
 #include "content/browser/compositor/image_transport_factory.h"
 #include "gpu/ipc/client/gpu_channel_host.h"
@@ -30,6 +31,7 @@ class VulkanInProcessContextProvider;
 
 namespace ui {
 class ContextProviderCommandBuffer;
+class DisplayCompositor;
 }
 
 namespace content {
@@ -78,6 +80,7 @@ class GpuProcessTransportFactory : public ui::ContextFactory,
   ui::ContextFactory* GetContextFactory() override;
   ui::ContextFactoryPrivate* GetContextFactoryPrivate() override;
   cc::SurfaceManager* GetSurfaceManager() override;
+  cc::mojom::DisplayCompositor* GetDisplayCompositor() override;
   display_compositor::GLHelper* GetGLHelper() override;
   void SetGpuChannelEstablishFactory(
       gpu::GpuChannelEstablishFactory* factory) override;
@@ -104,7 +107,11 @@ class GpuProcessTransportFactory : public ui::ContextFactory,
   scoped_refptr<cc::VulkanInProcessContextProvider>
   SharedVulkanContextProvider();
 
-  std::unique_ptr<cc::SurfaceManager> surface_manager_;
+  // Once all usage of SurfaceManager is removed, DisplayCompositor will only be
+  // used over Mojo and |display_compositor_| will be owned somewhere else.
+  cc::mojom::DisplayCompositorPtr display_compositor_ptr_;
+  std::unique_ptr<ui::DisplayCompositor> display_compositor_;
+
   cc::FrameSinkIdAllocator frame_sink_id_allocator_;
 
 #if defined(OS_WIN)