Introduce FrameSinkManagerHost in content/browser/.

content/browser/compositor/image_transport_factory.h

Index: content/browser/compositor/image_transport_factory.h
diff --git a/content/browser/compositor/image_transport_factory.h b/content/browser/compositor/image_transport_factory.h
index db669cc27fa90df06a032e9a6e9959d2d5d3670a..ec85572aaecda5fe76f3912cf5e9c7022c2a481a 100644
--- a/content/browser/compositor/image_transport_factory.h
+++ b/content/browser/compositor/image_transport_factory.h
@@ -35,6 +35,8 @@ class GpuChannelEstablishFactory;
 
 namespace content {
 
+class FrameSinkManagerHost;
+
 // This class provides the interface for creating the support for the
 // cross-process image transport, both for creating the shared surface handle
 // (destination surface for the GPU process) and the transport client (logic for
@@ -70,6 +72,9 @@ class CONTENT_EXPORT ImageTransportFactory {
   // (ImageTransportFactoryObserver::OnLostResources is called).
   virtual display_compositor::GLHelper* GetGLHelper() = 0;
 
+  // Gets the frame sink manager host instance.
+  virtual FrameSinkManagerHost* GetFrameSinkManagerHost() = 0;
+
   virtual void SetGpuChannelEstablishFactory(
       gpu::GpuChannelEstablishFactory* factory) = 0;