Add scale factor tag to data packs

ui/base/resource/resource_handle.h

Index: ui/base/resource/resource_handle.h
diff --git a/ui/base/resource/resource_handle.h b/ui/base/resource/resource_handle.h
index ce3a23bb2899381c5f4bf194ac135f526e6be1da..bda57613f02393e0ac5a459df0258ee2498dff6c 100644
--- a/ui/base/resource/resource_handle.h
+++ b/ui/base/resource/resource_handle.h
@@ -25,6 +25,10 @@ class UI_EXPORT ResourceHandle {
     UTF16
   };
 
+  // The scale factors for image resources.
+  static const float kScaleFactor1x;

[Jói, 2012/04/26 11:02:05]

Idea:  Using percentage-based naming might make for better constant names for
various non-integral scale factors, since we can't put a . in identifiers.  That
would name these constants as kScaleFactor100 and kScaleFactor200.

[sail, 2012/05/01 04:16:02]

Done.

+  static const float kScaleFactor2x;

[oshima, 2012/04/26 15:32:10]

I *think* you can just do static const float kScaleFactor2x = 1.0f;

[sail, 2012/05/01 04:16:02]

Unfortunately this only works for ints. For floats you need to put it in the CC
file.

+
   virtual ~ResourceHandle() {}
 
   // Get resource by id |resource_id|, filling in |data|.
@@ -40,6 +44,10 @@ class UI_EXPORT ResourceHandle {
 
   // Get the encoding type of text resources.
   virtual TextEncodingType GetTextEncodingType() const = 0;
+
+  // The scale of images in this resource pack relative to images in the 1x
+  // resource pak.
+  virtual float GetScaleFactor() const = 0;
 };
 
 }  // namespace ui