Fix dart editor buildbot scripts to support clobbering.

client/tools/buildbot_annotated_steps.py

 # Copyright (c) 2011, 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.
 
 #!/usr/bin/python
 
 # Copyright (c) 2011 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.
 
@@ skipping 120 matching lines @@
 
 def FixJavaHome():
   buildbot_javahome = os.getenv('BUILDBOT_JAVA_HOME')
   if buildbot_javahome:
     current_pwd = os.getenv('PWD')
     java_home = os.path.join(current_pwd, buildbot_javahome)
     os.environ['JAVA_HOME'] = java_home
     print 'Setting java home to'
     print java_home
 
+def ClobberBuilder():
+  """ Clobber the builder before we do the build.
+  Args:
+     - mode: either 'debug' or 'release'
+  """
+  cmd = [sys.executable,
+         './tools/clean_output_directory.py']
+  print 'Clobbering %s' % (' '.join(cmd))
+  return subprocess.call(cmd, env=NO_COLOR_ENV)
+
+def GetShouldClobber():
+  return os.environ.get(BUILDER_CLOBBER) == "1"
 
 def main():
   print 'main'
   if len(sys.argv) == 0:
     print 'Script pathname not known, giving up.'
     return 1
 
   scriptdir = os.path.dirname(sys.argv[0])
   # Get at the top-level directory. This script is in client/tools
   os.chdir(os.path.abspath(os.path.join(scriptdir, os.pardir, os.pardir)))
 
+  if GetShouldClobber():
+    print '@@@BUILD_STEP Clobber@@@'
+    status = ClobberBuilder()
+    if status != 0:
+      print '@@@STEP_FAILURE@@@'
+      return status
+
+
   #TODO(sigmund): remove this indirection once we update our bots
   (name, version) = GetBuildInfo()
   if name.startswith('dart-editor'):
     # TODO (danrubel) Fix dart-editor builds so that we can call FixJavaHome() before the build
     status = ProcessTools('release', name, version)
   else:
     # The buildbot will set a BUILDBOT_JAVA_HOME relative to the dart
     # root directory, set JAVA_HOME based on that.
     FixJavaHome()
     status = ProcessCompiler(name)
 
   if status:
     print '@@@STEP_FAILURE@@@'
 
   return status
 
 
 if __name__ == '__main__':
   sys.exit(main())