Add |git cl description| to allow you to change the description in your favorite $EDITOR.

R=maruel@chromium.org

Review URL: https://codereview.chromium.org/15302014

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@201094 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/git_cl.py b/git_cl.py
index cd477b9..6b735ad 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -1120,6 +1120,17 @@
   return 0
 
 
+def CMDdescription(parser, args):
+  """brings up the editor for the current CL's description."""
+  cl = Changelist()
+  if not cl.GetIssue():
+    DieWithError('This branch has no associated changelist.')
+  description = ChangeDescription(cl.GetDescription())
+  description.prompt()
+  cl.UpdateDescription(description.description)
+  return 0
+
+
 def CreateDescriptionFromLog(args):
   """Pulls out the commit log to use as a base for the CL description."""
   log_args = []