Move DIP translation from ui/aura to ui/compositor

ui/gfx/compositor/layer.h

 // 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.
 
 #ifndef UI_GFX_COMPOSITOR_LAYER_H_
 #define UI_GFX_COMPOSITOR_LAYER_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 18 matching lines @@
 namespace ui {
 
 class Compositor;
 class LayerAnimator;
 class Texture;
 
 // Layer manages a texture, transform and a set of child Layers. Any View that
 // has enabled layers ends up creating a Layer to manage the texture.
 // A Layer can also be created without a texture, in which case it renders
 // nothing and is simply used as a node in a hierarchy of layers.
+// Coordinate system used in layers is DIP (Density Independent Pixel)
+// coordinates unless explicitly mentioned as pixel coordinates.
 //
 // NOTE: unlike Views, each Layer does *not* own its children views. If you
 // delete a Layer and it has children, the parent of each child layer is set to
 // NULL, but the children are not deleted.
 class COMPOSITOR_EXPORT Layer :
     public LayerAnimationDelegate,
     NON_EXPORTED_BASE(public WebKit::WebContentLayerClient) {
  public:
   Layer();
   explicit Layer(LayerType type);
@@ skipping 137 matching lines @@
   void ScheduleDraw();
 
   // Sends damaged rectangles recorded in |damaged_region_| to
   // |compostior_| to repaint the content.
   void SendDamagedRects();
 
   // Suppresses painting the content by disgarding damaged region and ignoring
   // new paint requests.
   void SuppressPaint();
 
+  // Notifies the layer that the device scale factor has changed.
+  void OnDeviceScaleFactorChanged(float device_scale_factor);
+
+  // Sets if the layer should scale the canvas before passing to
+  // |LayerDelegate::OnLayerPaint|. Set to false if the delegate
+  // handles scaling.
+  void set_scale_canvas(bool scale_canvas);
+
   // Sometimes the Layer is being updated by something other than SetCanvas
   // (e.g. the GPU process on UI_COMPOSITOR_IMAGE_TRANSPORT).
   bool layer_updated_externally() const { return layer_updated_externally_; }
 
   // WebContentLayerClient
   virtual void paintContents(WebKit::WebCanvas*, const WebKit::WebRect& clip);
 
   WebKit::WebLayer web_layer() { return web_layer_; }
 
+  float device_scale_factor() const { return device_scale_factor_; }
+
  private:
   struct LayerProperties {
    public:
     ui::Layer* layer;
     ui::Transform transform_relative_to_root;
   };
 
   // TODO(vollick): Eventually, if a non-leaf node has an opacity of less than
   // 1.0, we'll render to a separate texture, and then apply the alpha.
   // Currently, we multiply our opacity by all our ancestor's opacities and
@@ skipping 54 matching lines @@
   gfx::Rect bounds_;
 
   // Visibility of this layer. See SetVisible/IsDrawn for more details.
   bool visible_;
 
   bool fills_bounds_opaquely_;
 
   // If true the layer is always up to date.
   bool layer_updated_externally_;
 
-  // Union of damaged rects to be used when compositor is ready to
-  // paint the content.
+  // Union of damaged rects, in pixel coordinates, to be used when
+  // compositor is ready to paint the content.
   SkRegion damaged_region_;
 
   float opacity_;
   int background_blur_radius_;
 
   std::string name_;
 
   LayerDelegate* delegate_;
 
   scoped_ptr<LayerAnimator> animator_;
 
   WebKit::WebLayer web_layer_;
   bool web_layer_is_accelerated_;
   bool show_debug_borders_;
 
+  // If true, the layer scales the canvas using device scale factor
+  // before passing to LayerDelegate::OnLayerPaint.
+  bool scale_canvas_;
+
+  // A cached copy of |Compositor::device_scale_factor()|.
+  float device_scale_factor_;
+
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace ui
 
 #endif  // UI_GFX_COMPOSITOR_LAYER_H_