Add "create_bundle" target in order to support bundle with gn.

tools/gn/functions.h

 // Copyright (c) 2013 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.
 
 #ifndef TOOLS_GN_FUNCTIONS_H_
 #define TOOLS_GN_FUNCTIONS_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 71 matching lines @@
 
 extern const char kBundleData[];
 extern const char kBundleData_HelpShort[];
 extern const char kBundleData_Help[];
 Value RunBundleData(Scope* scope,
                     const FunctionCallNode* function,
                     const std::vector<Value>& args,
                     BlockNode* block,
                     Err* err);
 
+extern const char kCreateBundle[];
+extern const char kCreateBundle_HelpShort[];
+extern const char kCreateBundle_Help[];
+Value RunCreateBundle(Scope* scope,
+                      const FunctionCallNode* function,
+                      const std::vector<Value>& args,
+                      BlockNode* block,
+                      Err* err);
+
 extern const char kConfig[];
 extern const char kConfig_HelpShort[];
 extern const char kConfig_Help[];
 Value RunConfig(const FunctionCallNode* function,
                 const std::vector<Value>& args,
                 Scope* block_scope,
                 Err* err);
 
 extern const char kCopy[];
 extern const char kCopy_HelpShort[];
@@ skipping 368 matching lines @@
   Scope* scope_;
   const FunctionCallNode* function_;
   const char* type_description_;
 
   // Set to true when the key is added to the scope so we don't try to
   // delete nonexistant keys which will cause assertions.
   bool key_added_;
 };
 
 #endif  // TOOLS_GN_FUNCTIONS_H_