Update the .pak file format to version 2: Make resource ids 16bit

chrome/browser/themes/browser_theme_pack.h

Index: chrome/browser/themes/browser_theme_pack.h
diff --git a/chrome/browser/themes/browser_theme_pack.h b/chrome/browser/themes/browser_theme_pack.h
index c2087511e0849a7fdad0f93795234ca7ea52a30b..fb748e90d9e91c084eab71c49e8991cadd142db1 100644
--- a/chrome/browser/themes/browser_theme_pack.h
+++ b/chrome/browser/themes/browser_theme_pack.h
@@ -103,8 +103,8 @@ class BrowserThemePack : public base::RefCountedThreadSafe<
   // The raw PNG memory associated with a certain id.
   typedef std::map<int, scoped_refptr<RefCountedMemory> > RawImages;
 
-  // The type passed to base::DataPack::WritePack.
-  typedef std::map<uint32, base::StringPiece> RawDataForWriting;
+  // The type passed to ui::DataPack::WritePack.
+  typedef std::map<uint16, base::StringPiece> RawDataForWriting;
 
   // An association between an id and the FilePath that has the image data.
   typedef std::map<int, FilePath> FilePathMap;