Speed up interop patch file creation

tools/dom/scripts/dartdomgenerator.py

Index: tools/dom/scripts/dartdomgenerator.py
diff --git a/tools/dom/scripts/dartdomgenerator.py b/tools/dom/scripts/dartdomgenerator.py
index b528141a15db4640ab14a53e20d92fd935d7cbc2..c0315df255fab90883a8ec9e92a640a2ef3b1189 100755
--- a/tools/dom/scripts/dartdomgenerator.py
+++ b/tools/dom/scripts/dartdomgenerator.py
@@ -234,6 +234,25 @@ def UpdateCssProperties():
   _logger.info('Updating Css Properties.')
   css_code_generator.GenerateCssTemplateFile()
 
+CACHED_PATCHES = """
+// START_OF_CACHED_PATCHES
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// DO NOT EDIT GENERATED FILE.
+
+library cached_patches;
+
+var cached_patches = {
+    /********************************************************
+     *****                                              *****
+     *****  MUST RUN tools/dartium/generate_patches.sh  *****
+     *****                                              *****
+     ********************************************************/
+};
+"""
+
 def main():
   parser = optparse.OptionParser()
   parser.add_option('--parallel', dest='parallel',
@@ -327,6 +346,14 @@ def main():
           os.path.join(dartium_output_dir, '%s_dartium.dart' % library_name),
           os.path.join('..', '..', '..', 'sdk', 'lib', library_name, 'dartium'))
 
+    # Blow away the cached_patches.dart needs to be re-generated for Dartium
+    # see tools/dartium/generate_patches.sh
+    cached_patches_filename = os.path.join('..', '..', '..', 'sdk', 'lib', 'js', 'dartium',
+                                           'cached_patches.dart')
+    cached_patches = open(cached_patches_filename, 'w')
+    cached_patches.write(CACHED_PATCHES);
+    cached_patches.close()
+
   if '_blink' in systems:
     _logger.info('Generating dartium _blink file.')
     file_generation_start_time = time.time()