Add scale factor tag to data packs

ui/base/resource/data_pack.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.
 
 // DataPack represents a read-only view onto an on-disk file that contains
 // (key, value) pairs of data.  It's used to store static resources like
 // translation strings and images.
 
 #ifndef UI_BASE_RESOURCE_DATA_PACK_H_
 #define UI_BASE_RESOURCE_DATA_PACK_H_
@@ skipping 14 matching lines @@
 }
 
 namespace file_util {
 class MemoryMappedFile;
 }
 
 namespace ui {
 
 class UI_EXPORT DataPack : public ResourceHandle {
  public:
-  DataPack();
+  DataPack(float scale_factor);
   virtual ~DataPack();
 
   // Load a pack file from |path|, returning false on error.
   bool Load(const FilePath& path);
 
   // Writes a pack file containing |resources| to |path|. If there are any
   // text resources to be written, their encoding must already agree to the
   // |textEncodingType| specified. If no text resources are present, please
   // indicate BINARY.
   static bool WritePack(const FilePath& path,
                         const std::map<uint16, base::StringPiece>& resources,
                         TextEncodingType textEncodingType);
 
   // ResourceHandle implementation:
   virtual bool GetStringPiece(uint16 resource_id,
                               base::StringPiece* data) const OVERRIDE;
   virtual base::RefCountedStaticMemory* GetStaticMemory(
       uint16 resource_id) const OVERRIDE;
   virtual TextEncodingType GetTextEncodingType() const OVERRIDE;
+  virtual float GetScaleFactor() const OVERRIDE;
 
  private:
   // The memory-mapped data.
   scoped_ptr<file_util::MemoryMappedFile> mmap_;
 
   // Number of resources in the data.
   size_t resource_count_;
 
   // Type of encoding for text resources.
   TextEncodingType text_encoding_type_;
 
+  // The scale of the image in this resource pack relative to images in the 1x
+  // resource pak.
+  float scale_factor_;
+
   DISALLOW_COPY_AND_ASSIGN(DataPack);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_RESOURCE_DATA_PACK_H_