Parse messages.json in ExtensionUnpacker (like we do for manifest)....

chrome/common/extensions/extension_unpacker.h

Index: chrome/common/extensions/extension_unpacker.h
===================================================================
--- chrome/common/extensions/extension_unpacker.h	(revision 32098)
+++ chrome/common/extensions/extension_unpacker.h	(working copy)
@@ -46,16 +46,24 @@
     return parsed_manifest_.get();
   }
   const DecodedImages& decoded_images() { return decoded_images_; }
+  DictionaryValue* parsed_catalogs() { return parsed_catalogs_.get(); }
 
  private:
   // Parse the manifest.json file inside the extension (not in the header).
   // Caller takes ownership of return value.
   DictionaryValue* ReadManifest();
 
+  // Parse all _locales/*/messages.json files inside the extension.
+  bool ReadAllMessageCatalogs(const std::string& default_locale);
+
   // Decodes the image at the given path and puts it in our list of decoded
   // images.
   bool AddDecodedImage(const FilePath& path);
 
+  // Parses the catalog at the given path and puts it in our list of parsed
+  // catalogs.
+  bool ReadMessageCatalog(const FilePath& message_path);
+
   // Set the error message.
   void SetError(const std::string& error);
 
@@ -72,6 +80,10 @@
   // are relative to the manifest file.
   DecodedImages decoded_images_;
 
+  // Dictionary of relative paths and catalogs per path. Paths are in the form
+  // of _locales/locale, without messages.json base part.
+  scoped_ptr<DictionaryValue> parsed_catalogs_;
+
   // The last error message that was set.  Empty if there were no errors.
   std::string error_message_;