Speed up fremontcut/dartdomgenerator

lib/html/scripts/dartdomgenerator.py

Index: lib/html/scripts/dartdomgenerator.py
diff --git a/lib/html/scripts/dartdomgenerator.py b/lib/html/scripts/dartdomgenerator.py
index 469d49159eec1254220db4e1f04ffeddbf5f08c7..27cbe6489016c39ee62c5dfd1ed9837be63f9cda 100755
--- a/lib/html/scripts/dartdomgenerator.py
+++ b/lib/html/scripts/dartdomgenerator.py
@@ -7,6 +7,7 @@
 
 import dartgenerator
 import database
+import fremontcutbuilder
 import logging.config
 import multiemitter
 import optparse
@@ -37,20 +38,28 @@ _webkit_renames = {
     'Window': 'DOMWindow',
     'WorkerGlobalScope': 'WorkerContext'}
 
+# TODO(vsm): Remove once we fix Dartium to pass in the database directly.
 def Generate(database_dir, use_database_cache, dart2js_output_dir=None,
              dartium_output_dir=None):
-  current_dir = os.path.dirname(__file__)
-  auxiliary_dir = os.path.join(current_dir, '..', 'src')
-  template_dir = os.path.join(current_dir, '..', 'templates')
-
-  generator = dartgenerator.DartGenerator()
-  generator.LoadAuxiliary(auxiliary_dir)
+  database = LoadDatabase(database_dir, use_database_cache)
+  GenerateFromDatabase(database, dart2js_output_dir, dartium_output_dir)
 
+def LoadDatabase(database_dir, use_database_cache):
   common_database = database.Database(database_dir)
   if use_database_cache:
     common_database.LoadFromCache()
   else:
     common_database.Load()
+  return common_database
+
+def GenerateFromDatabase(common_database, dart2js_output_dir,
+                         dartium_output_dir):
+  current_dir = os.path.dirname(__file__)
+  auxiliary_dir = os.path.join(current_dir, '..', 'src')
+  template_dir = os.path.join(current_dir, '..', 'templates')
+
+  generator = dartgenerator.DartGenerator()
+  generator.LoadAuxiliary(auxiliary_dir)
 
   generator.FilterMembersWithUnidentifiedTypes(common_database)
   webkit_database = common_database.Clone()
@@ -110,6 +119,9 @@ def GenerateSingleFile(library_path, output_dir):
 
 def main():
   parser = optparse.OptionParser()
+  parser.add_option('--rebuild', dest='rebuild',
+                    action='store_true', default=False,
+                    help='Rebuild the database from IDL using fremontcut.')
   parser.add_option('--systems', dest='systems',
                     action='store', type='string',
                     default='htmldart2js,htmldartium',
@@ -138,8 +150,14 @@ def main():
   if 'htmldartium' in systems:
     dartium_output_dir = os.path.join(output_dir, 'dartium')
 
-  Generate(database_dir, options.use_database_cache, dart2js_output_dir,
-           dartium_output_dir)
+  if options.rebuild:
+    # Parse the IDL and create the database.
+    database = fremontcutbuilder.main()
+  else:
+    # Load the previously generated database.
+    database = LoadDatabase(database_dir, options.use_database_cache)
+  GenerateFromDatabase(database, dart2js_output_dir,
+                       dartium_output_dir)
 
   if 'htmldart2js' in systems:
     _logger.info('Copy html_dart2js to dart2js/')