Revamp OffscreenCanvas commit flow

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
index bd018fb2bb42717c660af90e3f0df765951d9797..cbe4410132a331d9ee361e1c21d21ab03b6f93ed 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -38,6 +38,7 @@
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/TaskRunnerHelper.h"
 #include "core/fileapi/File.h"
+#include "core/frame/FrameView.h"
 #include "core/frame/ImageBitmap.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
@@ -54,6 +55,8 @@
 #include "core/imagebitmap/ImageBitmapOptions.h"
 #include "core/layout/HitTestCanvasResult.h"
 #include "core/layout/LayoutHTMLCanvas.h"
+#include "core/layout/api/LayoutViewItem.h"
+#include "core/layout/compositing/PaintLayerCompositor.h"
 #include "core/paint/PaintLayer.h"
 #include "core/paint/PaintTiming.h"
 #include "platform/Histogram.h"
@@ -1397,15 +1400,19 @@ String HTMLCanvasElement::getIdFromControl(const Element* element) {
   return String();
 }
 
-bool HTMLCanvasElement::createSurfaceLayer() {
+void HTMLCanvasElement::createLayer() {
   DCHECK(!m_surfaceLayerBridge);
   mojom::blink::OffscreenCanvasSurfacePtr service;
   Platform::current()->interfaceProvider()->getInterface(
       mojo::GetProxy(&service));
   m_surfaceLayerBridge =
-      WTF::wrapUnique(new CanvasSurfaceLayerBridge(std::move(service)));
-  return m_surfaceLayerBridge->createSurfaceLayer(this->width(),
-                                                  this->height());
+      WTF::wrapUnique(new CanvasSurfaceLayerBridge(std::move(service), this));
+  // Creates a placeholder layer first before Surface is created.
+  m_surfaceLayerBridge->createSolidColorLayer();
+}
+
+void HTMLCanvasElement::OnWebLayerReplaced() {
+  setNeedsCompositingUpdate();
 }
 
 }  // namespace blink