Add non-blocking frame rate limiting logic to display list 2D canvas

Source/core/html/HTMLCanvasElement.cpp

Index: Source/core/html/HTMLCanvasElement.cpp
diff --git a/Source/core/html/HTMLCanvasElement.cpp b/Source/core/html/HTMLCanvasElement.cpp
index 25fbe5b60f7e7363801255dd719ecd49b0350a31..748984dd3c7bed4e4fcee948f5c9b2d721df15e8 100644
--- a/Source/core/html/HTMLCanvasElement.cpp
+++ b/Source/core/html/HTMLCanvasElement.cpp
@@ -195,6 +195,9 @@ void HTMLCanvasElement::didDraw(const FloatRect& rect)
 {
     clearCopiedImage();
 
+    if (hasImageBuffer())
+        m_imageBuffer->didDraw();
+
     if (RenderBox* ro = renderBox()) {
         FloatRect srcRect(0, 0, size().width(), size().height());
         FloatRect r = rect;