Tag TransportDIBs with the device scale factor they expect.

content/browser/renderer_host/test_backing_store.cc

 // Copyright (c) 2011 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 "content/browser/renderer_host/test_backing_store.h"
 
 TestBackingStore::TestBackingStore(content::RenderWidgetHost* widget,
                                    const gfx::Size& size)
     : BackingStore(widget, size) {
 }
 
 TestBackingStore::~TestBackingStore() {
 }
 
 void TestBackingStore::PaintToBackingStore(
     content::RenderProcessHost* process,
     TransportDIB::Id bitmap,
     const gfx::Rect& bitmap_rect,
     const std::vector<gfx::Rect>& copy_rects,
+    float scale_factor,
     const base::Closure& completion_callback,
     bool* scheduled_completion_callback) {
   *scheduled_completion_callback = false;
 }
 
 bool TestBackingStore::CopyFromBackingStore(const gfx::Rect& rect,
                                             skia::PlatformCanvas* output) {
   return false;
 }
 
 void TestBackingStore::ScrollBackingStore(int dx, int dy,
                                           const gfx::Rect& clip_rect,
                                           const gfx::Size& view_size) {
 }