Add patch file support to Dart embedder

mojo/dart/embedder/builtin.h

 // Copyright 2014 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 MOJO_DART_EMBEDDER_BUILTIN_H_
 #define MOJO_DART_EMBEDDER_BUILTIN_H_
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 38 matching lines @@
 
   static Dart_Handle NewError(const char* format, ...);
 
  private:
   // Native method support.
   static Dart_NativeFunction NativeLookup(Dart_Handle name,
                                           int argument_count,
                                           bool* auto_setup_scope);
 
   static const uint8_t* NativeSymbol(Dart_NativeFunction nf);
-
+  static Dart_Handle ReadStringFromFile(const char* file);
+  static void LoadPatchFiles(Dart_Handle library,
+                             const char* patch_uri,
+                             const char** patch_files);
   typedef struct {
     const char* url_;
     bool has_natives_;
     Dart_NativeEntrySymbol native_symbol_;
     Dart_NativeEntryResolver native_resolver_;
+    const char* patch_url_;
+    const char** patch_paths_;
   } builtin_lib_props;
   static builtin_lib_props builtin_libraries_[];
 
+  static const char* mojo_core_patch_paths_[];
   DISALLOW_IMPLICIT_CONSTRUCTORS(Builtin);
 };
 
 }  // namespace dart
 }  // namespace mojo
 
 #endif  // MOJO_DART_EMBEDDER_BUILTIN_H_