Introduce painted-device-scale-factor and use it when --enable-use-zoom-for-dsf is specified.

cc/trees/layer_tree_host.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.h"
 
 #include <algorithm>
 #include <stack>
 #include <string>
 
@@ skipping 81 matching lines @@
       source_frame_number_(0),
       meta_information_sequence_number_(1),
       rendering_stats_instrumentation_(RenderingStatsInstrumentation::Create()),
       output_surface_lost_(true),
       settings_(*params->settings),
       debug_state_(settings_.initial_debug_state),
       top_controls_shrink_blink_size_(false),
       top_controls_height_(0.f),
       top_controls_shown_ratio_(0.f),
       device_scale_factor_(1.f),
+      painted_device_scale_factor_(1.f),
       visible_(false),
       page_scale_factor_(1.f),
       min_page_scale_factor_(1.f),
       max_page_scale_factor_(1.f),
       has_gpu_rasterization_trigger_(false),
       content_is_suitable_for_gpu_rasterization_(true),
       gpu_rasterization_histogram_recorded_(false),
       background_color_(SK_ColorWHITE),
       has_transparent_background_(false),
       did_complete_scale_animation_(false),
@@ skipping 192 matching lines @@
   host_impl->SetHasGpuRasterizationTrigger(has_gpu_rasterization_trigger_);
   host_impl->SetContentIsSuitableForGpuRasterization(
       content_is_suitable_for_gpu_rasterization_);
   RecordGpuRasterizationHistogram();
 
   host_impl->SetViewportSize(device_viewport_size_);
   // TODO(senorblanco): Move this up so that it happens before GPU rasterization
   // properties are set, since those trigger an update of GPU rasterization
   // status, which depends on the device scale factor. (crbug.com/535700)
   sync_tree->SetDeviceScaleFactor(device_scale_factor_);
+  sync_tree->set_painted_device_scale_factor(painted_device_scale_factor_);
   host_impl->SetDebugState(debug_state_);
   if (pending_page_scale_animation_) {
     sync_tree->SetPendingPageScaleAnimation(
         pending_page_scale_animation_.Pass());
   }
 
   if (!ui_resource_request_queue_.empty()) {
     sync_tree->set_ui_resource_request_queue(ui_resource_request_queue_);
     ui_resource_request_queue_.clear();
   }
@@ skipping 540 matching lines @@
 
 void LayerTreeHost::SetDeviceScaleFactor(float device_scale_factor) {
   if (device_scale_factor == device_scale_factor_)
     return;
   device_scale_factor_ = device_scale_factor;
 
   property_trees_.needs_rebuild = true;
   SetNeedsCommit();
 }
 
+void LayerTreeHost::SetPaintedDeviceScaleFactor(
+    float painted_device_scale_factor) {
+  if (painted_device_scale_factor == painted_device_scale_factor_)
+    return;
+  painted_device_scale_factor_ = painted_device_scale_factor;
+
+  SetNeedsCommit();
+}
+
 void LayerTreeHost::UpdateTopControlsState(TopControlsState constraints,
                                            TopControlsState current,
                                            bool animate) {
   // Top controls are only used in threaded mode.
   DCHECK(proxy_->HasImplThread());
   proxy_->UpdateTopControlsState(constraints, current, animate);
 }
 
 void LayerTreeHost::AnimateLayers(base::TimeTicks monotonic_time) {
   if (!settings_.accelerated_animation_enabled)
@@ skipping 336 matching lines @@
   return animation_host_ ? animation_host_->HasAnyAnimation(layer->id())
                          : false;
 }
 
 bool LayerTreeHost::HasActiveAnimation(const Layer* layer) const {
   return animation_host_ ? animation_host_->HasActiveAnimation(layer->id())
                          : false;
 }
 
 }  // namespace cc