Add support for loading pak files from arbitrary file regions.

ui/base/resource/resource_bundle.h

Index: ui/base/resource/resource_bundle.h
diff --git a/ui/base/resource/resource_bundle.h b/ui/base/resource/resource_bundle.h
index 1f40728ac25f1717f748a65e4fd7625b802504c2..9e5b94e22e8cd4d50157118b6dea94f203b3240f 100644
--- a/ui/base/resource/resource_bundle.h
+++ b/ui/base/resource/resource_bundle.h
@@ -10,6 +10,7 @@
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
+#include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
@@ -26,7 +27,6 @@
 class SkBitmap;
 
 namespace base {
-class File;
 class Lock;
 class RefCountedStaticMemory;
 }
@@ -166,6 +166,11 @@ class UI_BASE_EXPORT ResourceBundle {
   // Same as above but using an already open file.
   void AddDataPackFromFile(base::File file, ScaleFactor scale_factor);
 
+  // Same as above but using only a region (offset + size) of the file.
+  void AddDataPackFromFileRegion(base::File file,
+                                 const base::File::Region& region,
+                                 ScaleFactor scale_factor);
+
   // Same as AddDataPackFromPath but does not log an error if the pack fails to
   // load.
   void AddOptionalDataPackFromPath(const base::FilePath& path,