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

cc/trees/layer_tree_impl.h

Index: cc/trees/layer_tree_impl.h
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 6d544387ff94b6667ecb4d17b4bf82b98c1d55b7..54f9d6c3f37143cd514503e0bea21cd1ca040dac 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -197,7 +197,11 @@ class CC_EXPORT LayerTreeImpl {
   const SyncedProperty<ScaleGroup>* page_scale_factor() const;
 
   void SetDeviceScaleFactor(float device_scale_factor);
+  void SetPaintedDeviceScaleFactor(float painted_device_scale_factor);

[danakj, 2015/10/22 23:15:29]

nit: normally keep the set/get pair together for each var

[oshima, 2015/10/23 18:05:36]

Done.

   float device_scale_factor() const { return device_scale_factor_; }
+  float painted_device_scale_factor() const {
+    return painted_device_scale_factor_;
+  }
 
   SyncedElasticOverscroll* elastic_overscroll() {
     return elastic_overscroll_.get();
@@ -438,6 +442,7 @@ class CC_EXPORT LayerTreeImpl {
   float max_page_scale_factor_;
 
   float device_scale_factor_;
+  float painted_device_scale_factor_;
 
   scoped_refptr<SyncedElasticOverscroll> elastic_overscroll_;