Move DIP translation from ui/aura to ui/compositor

ui/gfx/compositor/layer.h

Index: ui/gfx/compositor/layer.h
diff --git a/ui/gfx/compositor/layer.h b/ui/gfx/compositor/layer.h
index 77237d224afdf00854a405354593f593eea5d5a2..44e3ac8094c605eb36ca87eb26277621dbbff49e 100644
--- a/ui/gfx/compositor/layer.h
+++ b/ui/gfx/compositor/layer.h
@@ -36,6 +36,8 @@ class Texture;
 // 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
@@ -113,6 +115,10 @@ class COMPOSITOR_EXPORT Layer :
   void SetBounds(const gfx::Rect& bounds);
   const gfx::Rect& bounds() const { return bounds_; }
 
+  // Sets/Gets the bounds in pixel coordinates, relative to the parent.
+  void SetBoundsInPixel(const gfx::Rect& bounds_in_dip);
+  gfx::Rect GetBoundsInPixel() const;

[piman, 2012/05/04 18:46:06]

Are these called publicly (or at all?)

+
   // Return the target bounds if animator is running, or the current bounds
   // otherwise.
   gfx::Rect GetTargetBounds() const;
@@ -193,6 +199,14 @@ class COMPOSITOR_EXPORT Layer :
   // new paint requests.
   void SuppressPaint();
 
+  // Update the layer's size in pixel using the current device scale factor.
+  void UpdateLayerSize();
+
+  // 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_; }
@@ -276,8 +290,8 @@ class COMPOSITOR_EXPORT Layer :
   // 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_;
@@ -293,6 +307,10 @@ class COMPOSITOR_EXPORT 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::OnLayerPaitn.

[piman, 2012/05/04 18:46:06]

nit: OnLayerPaitn -> OnLayerPaint

+  bool scale_canvas_;
+
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };