Make tile size a function of the device scale factor.

cc/trees/layer_tree_host_impl.cc

 // Copyright 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 "cc/trees/layer_tree_host_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 2394 matching lines @@
 }
 
 const gfx::Rect LayerTreeHostImpl::ViewportRectForTilePriority() const {
   if (viewport_rect_for_tile_priority_.IsEmpty())
     return DeviceViewport();
 
   return viewport_rect_for_tile_priority_;
 }
 
 gfx::Size LayerTreeHostImpl::DrawViewportSize() const {
+  // XXX DIE DIE DIE DIE
   return DeviceViewport().size();
 }
 
 gfx::Rect LayerTreeHostImpl::DeviceViewport() const {
   if (external_viewport_.IsEmpty())
     return gfx::Rect(device_viewport_size_);
 
   return external_viewport_;
 }
 
@@ skipping 1581 matching lines @@
   return task_runner_provider_->HasImplThread();
 }
 
 bool LayerTreeHostImpl::CommitToActiveTree() const {
   // In single threaded mode we skip the pending tree and commit directly to the
   // active tree.
   return !task_runner_provider_->HasImplThread();
 }
 
 }  // namespace cc