Add property to CssStyleDeclaration to detect if a CSS value is available.

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 d9e1837695ceac8cd4e742c83f8b940d00b439e0..adc7814842edbecf97e287654f752765d7e89c4f 100755
--- a/tools/dom/scripts/dartdomgenerator.py
+++ b/tools/dom/scripts/dartdomgenerator.py
@@ -5,6 +5,7 @@
 
 """This is the entry point to create Dart APIs from the IDL database."""
 
+import css_code_generator
 import dartgenerator
 import database
 import fremontcutbuilder
@@ -163,6 +164,12 @@ def GenerateSingleFile(library_path, output_dir, generated_output_dir=None):
                       copy_dart_script, output_dir, library_filename])
   subprocess.call([command], shell=True)
 
+def UpdateCssProperties():
+  """Regenerate the CssStyleDeclaration template file with the current CSS
+  properties."""
+  _logger.info('Updating Css Properties.')
+  css_code_generator.GenerateCssTemplateFile()
+
 def main():
   parser = optparse.OptionParser()
   parser.add_option('--parallel', dest='parallel',
@@ -210,6 +217,7 @@ def main():
   if 'htmldartium' in systems:
     dartium_output_dir = os.path.join(output_dir, 'dartium')
 
+  UpdateCssProperties()
   if options.rebuild:
     # Parse the IDL and create the database.
     database = fremontcutbuilder.main(options.parallel)