Tag TransportDIBs with the device scale factor they expect.

content/browser/renderer_host/backing_store_gtk.cc

 // 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.
 
 #include "content/browser/renderer_host/backing_store_gtk.h"
 
 #include <cairo-xlib.h>
 #include <gtk/gtk.h>
 #include <stdlib.h>
 #include <sys/ipc.h>
@@ skipping 316 matching lines @@
   }
 
   XFreePixmap(display_, pixmap);
 }
 
 void BackingStoreGtk::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;
 
   if (!display_)
     return;
 
   if (bitmap_rect.IsEmpty())
     return;
 
@@ skipping 308 matching lines @@
   cairo_set_source(cr, pattern);
   cairo_pattern_destroy(pattern);
 
   cairo_identity_matrix(cr);
 
   cairo_rectangle(cr, rect.x(), rect.y(), rect.width(), rect.height());
   cairo_fill(cr);
   cairo_destroy(cr);
 }
 #endif