Change the scale factor of texture_size from the layer's one to an estimation.

ui/compositor/layer.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_COMPOSITOR_LAYER_H_
 #define UI_COMPOSITOR_LAYER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 376 matching lines @@
   bool web_layer_is_accelerated_;
   bool show_debug_borders_;
 
   // If true, the layer scales the canvas and the texture with the device scale
   // factor as appropriate. When true, the texture size is in DIP.
   bool scale_content_;
 
   // A cached copy of |Compositor::device_scale_factor()|.
   float device_scale_factor_;
 
+  // The device scale factor when |texture_| is provided.  This is mostly same
+  // as |device_scale_factor_| itself but could be inconsistent in some special
+  // cases.
+  float device_scale_factor_for_texture_;
+
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_H_