Avoid GPU readback in tex(Sub)Image2D(ImageBitmap)

third_party/WebKit/Source/core/frame/ImageBitmap.cpp

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/frame/ImageBitmap.h"
 
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/ImageData.h"
 #include "platform/graphics/skia/SkiaUtils.h"
@@ skipping 450 matching lines @@
 }
 
 unsigned long ImageBitmap::height() const
 {
     if (!m_image)
         return 0;
     ASSERT(m_image->height() > 0);
     return m_image->height();
 }
 
+bool ImageBitmap::isTextureBacked() const
+{
+    return m_image && (m_image->isTextureBacked() || m_image->hasMailbox());
+}
+
 IntSize ImageBitmap::size() const
 {
     if (!m_image)
         return IntSize();
     ASSERT(m_image->width() > 0 && m_image->height() > 0);
     return IntSize(m_image->width(), m_image->height());
 }
 
 ScriptPromise ImageBitmap::createImageBitmap(ScriptState* scriptState, EventTarget& eventTarget, int sx, int sy, int sw, int sh, const ImageBitmapOptions& options, ExceptionState& exceptionState)
 {
@@ skipping 33 matching lines @@
 FloatSize ImageBitmap::elementSize(const FloatSize&) const
 {
     return FloatSize(width(), height());
 }
 
 DEFINE_TRACE(ImageBitmap)
 {
 }
 
 } // namespace blink