Pass accurate contentsScale to LayerImpl.

cc/image_layer.cc

 // Copyright 2010 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 "config.h"
 
 #include "cc/image_layer.h"
 
 #include "base/compiler_specific.h"
 #include "cc/layer_updater.h"
@@ skipping 132 matching lines @@
 IntSize ImageLayer::contentBounds() const
 {
     return IntSize(m_bitmap.width(), m_bitmap.height());
 }
 
 bool ImageLayer::drawsContent() const
 {
     return !m_bitmap.isNull() && TiledLayer::drawsContent();
 }
 
-bool ImageLayer::needsContentsScale() const
+float ImageLayer::contentsScaleX() const
 {
-    // Contents scale is not need for image layer because this can be done in compositor more efficiently.
-    return false;
+    if (bounds().isEmpty())
+        return 1;
+    return static_cast<float>(m_bitmap.width()) / bounds().width();
+}
+
+float ImageLayer::contentsScaleY() const
+{
+    if (bounds().isEmpty())
+        return 1;
+    return static_cast<float>(m_bitmap.height()) / bounds().height();
 }
 
 }