Reland Submit Compositor Frame from OffscreenCanvas on main

third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h

Index: third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h
diff --git a/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h b/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h
index 162b2b874905d3185100ee844a0c8b06c5cfb778..5e6dd8b2fd0a5f897457132cf511c53ab0c04cb8 100644
--- a/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h
+++ b/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.h
@@ -11,6 +11,7 @@
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/canvas/CanvasImageSource.h"
 #include "platform/geometry/IntSize.h"
+#include "platform/graphics/OffscreenCanvasFrameDispatcher.h"
 #include "platform/heap/Handle.h"
 #include <memory>
 
@@ -50,6 +51,8 @@ public:
     // TODO(crbug.com/630356): apply the flag to WebGL context as well
     void setDisableReadingFromCanvasTrue() { m_disableReadingFromCanvas = true; }
 
+    OffscreenCanvasFrameDispatcher* getOrCreateFrameDispatcher();
+
     void setSurfaceId(uint32_t clientId, uint32_t localId, uint64_t nonce)
     {
         m_clientId = clientId;
@@ -88,6 +91,7 @@ private:
 
     bool isPaintable() const;
 
+    std::unique_ptr<OffscreenCanvasFrameDispatcher> m_frameDispatcher;
     // cc::SurfaceId is broken into three integer components as this can be used
     // in transfer of OffscreenCanvas across threads
     // If this object is not created via HTMLCanvasElement.transferControlToOffscreen(),