Tag TransportDIBs with the device scale factor they expect.

content/browser/renderer_host/backing_store_mac.mm

 // 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.
 
 #import <Cocoa/Cocoa.h>
 
 #include "content/browser/renderer_host/backing_store_mac.h"
 
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
@@ skipping 32 matching lines @@
 
 size_t BackingStoreMac::MemorySize() {
   return size().Scale(device_scale_factor_).GetArea() * 4;
 }
 
 void BackingStoreMac::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;
   DCHECK_NE(static_cast<bool>(cg_layer()), static_cast<bool>(cg_bitmap()));
 
   TransportDIB* dib = process->GetTransportDIB(bitmap);
   if (!dib)
     return;
 
   gfx::Size pixel_size = size().Scale(device_scale_factor_);
-  gfx::Rect pixel_bitmap_rect = bitmap_rect.Scale(device_scale_factor_);
+  gfx::Rect pixel_bitmap_rect = bitmap_rect.Scale(scale_factor);
 
   base::mac::ScopedCFTypeRef<CGDataProviderRef> data_provider(
       CGDataProviderCreateWithData(NULL, dib->memory(),
       pixel_bitmap_rect.width() * pixel_bitmap_rect.height() * 4, NULL));
 
   base::mac::ScopedCFTypeRef<CGImageRef> bitmap_image(
       CGImageCreate(pixel_bitmap_rect.width(), pixel_bitmap_rect.height(),
           8, 32, 4 * pixel_bitmap_rect.width(),
           base::mac::GetSystemColorSpace(),
           kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host,
           data_provider, NULL, false, kCGRenderingIntentDefault));
 
   for (size_t i = 0; i < copy_rects.size(); i++) {
     const gfx::Rect& copy_rect = copy_rects[i];
-    gfx::Rect pixel_copy_rect = copy_rect.Scale(device_scale_factor_);
+    gfx::Rect pixel_copy_rect = copy_rect.Scale(scale_factor);
 
     // Only the subpixels given by copy_rect have pixels to copy.
     base::mac::ScopedCFTypeRef<CGImageRef> image(
         CGImageCreateWithImageInRect(bitmap_image, CGRectMake(
             pixel_copy_rect.x() - pixel_bitmap_rect.x(),
             pixel_copy_rect.y() - pixel_bitmap_rect.y(),
             pixel_copy_rect.width(),
             pixel_copy_rect.height())));
 
     if (!cg_layer()) {
@@ skipping 164 matching lines @@
                                                pixel_size.width(),
                                                pixel_size.height(),
                                                8, pixel_size.width() * 4,
                                                base::mac::GetSystemColorSpace(),
                                                kCGImageAlphaPremultipliedFirst |
                                                    kCGBitmapByteOrder32Host);
   DCHECK(context);
 
   return context;
 }