Cancel GPU acceleration for 2D canvas when drawing very large images

third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp

Index: third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp
diff --git a/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp b/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp
index e1f5804c068f886da50a2f2a06dccb09a1989f6d..8d9427b506321abfaccd8e9cf2f0bf47896e6b01 100644
--- a/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp
+++ b/third_party/WebKit/Source/core/offscreencanvas/OffscreenCanvas.cpp
@@ -156,6 +156,11 @@ bool OffscreenCanvas::isPaintable() const
     return m_context->isPaintable();
 }
 
+bool OffscreenCanvas::isAccelerated() const
+{
+    return m_context && m_context->isAccelerated();

[xlai (Olivia), 2016/09/23 20:48:04]

Just want to let you know that in my previous patch I remove the
OffscreenCanvasRenderingContext2D::isAccelerated() overriding function based on
suggestion. So this function here may not return correct value
of Offscreen 2d context.

+}
+
 OffscreenCanvasFrameDispatcher* OffscreenCanvas::getOrCreateFrameDispatcher()
 {
     if (!m_frameDispatcher) {