Accelerate small canvases if Ganesh is on.

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 8b0d798af50c69d4d865d79bbb35a37064fa7925..5b5505bdcb2eb191bcb6596d88e81c9c5f9fed4d 100644
--- a/Source/core/html/HTMLCanvasElement.cpp
+++ b/Source/core/html/HTMLCanvasElement.cpp
@@ -43,6 +43,7 @@
 #include "core/html/canvas/WebGLContextAttributes.h"
 #include "core/html/canvas/WebGLContextEvent.h"
 #include "core/html/canvas/WebGLRenderingContext.h"
+#include "core/page/ChromeClient.h"
 #include "core/rendering/RenderHTMLCanvas.h"
 #include "platform/MIMETypeRegistry.h"
 #include "platform/graphics/Canvas2DImageBufferSurface.h"
@@ -431,8 +432,9 @@ bool HTMLCanvasElement::shouldAccelerate(const IntSize& size) const
     if (!settings || !settings->accelerated2dCanvasEnabled())
         return false;
 
-    // Do not use acceleration for small canvas.
-    if (size.width() * size.height() < settings->minimumAccelerated2dCanvasSize())
+    // Do not use acceleration for small canvases, unless GPU rasterization is available.
+    // GPU raterization is a heuristic to avoid difficult content & whitelist targeted content.
+    if (!document().frame()->chromeClient().usesGpuRasterization() && size.width() * size.height() < settings->minimumAccelerated2dCanvasSize())
         return false;
 
     if (!blink::Platform::current()->canAccelerate2dCanvas())