Do compositing update when switching from software to accelerated canvas

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 21d70d80aa0edf355c6bdc73be91a3626c2d1694..09f3f803c9ead81491149e9e2f324d95874ef9df 100644
--- a/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp
@@ -1235,6 +1235,7 @@ void HTMLCanvasElement::willDrawImageTo2DContext(CanvasImageSource* source) {
         createAcceleratedImageBufferSurface(opacityMode, &msaaSampleCount);
     if (surface) {
       buffer()->setSurface(std::move(surface));
+      setNeedsCompositingUpdate();
     }
   }
 }