Revert of 2D canvas: remain in deferred rendering mode with canvas to canvas drawImage

Source/modules/canvas2d/CanvasRenderingContext2D.cpp

Index: Source/modules/canvas2d/CanvasRenderingContext2D.cpp
diff --git a/Source/modules/canvas2d/CanvasRenderingContext2D.cpp b/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
index 4e3e06d2f42195553adec4d946b0c6b8eb677e55..41d48fe8be8d093508a6b6f92642f749708b670b 100644
--- a/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
+++ b/Source/modules/canvas2d/CanvasRenderingContext2D.cpp
@@ -1353,20 +1353,6 @@
     c->restoreToCount(initialSaveCount);
 }
 
-bool shouldDisableDeferral(CanvasImageSource* imageSource)
-{
-    if (imageSource->isVideoElement())
-        return true;
-    if (imageSource->isCanvasElement()) {
-        HTMLCanvasElement* canvas = static_cast<HTMLCanvasElement*>(imageSource);
-        if (canvas->is3D())
-            return true;
-        if (canvas->isAnimated2D())
-            return true;
-    }
-    return false;
-}
-
 void CanvasRenderingContext2D::drawImage(CanvasImageSource* imageSource,
     float sx, float sy, float sw, float sh,
     float dx, float dy, float dw, float dh, ExceptionState& exceptionState)
@@ -1402,7 +1388,12 @@
     if (srcRect.isEmpty())
         return;
 
-    if (shouldDisableDeferral(imageSource))
+    // FIXME: crbug.com/521001
+    // We make the destination canvas fall out of display list mode by forcing
+    // immediate rendering. This is to prevent run-away memory consumption caused by SkSurface
+    // copyOnWrite when the source canvas is animated and consumed at a rate higher than the
+    // presentation frame rate of the destination canvas.
+    if (imageSource->isVideoElement() || imageSource->isCanvasElement())
         canvas()->disableDeferral();
 
     validateStateStack();