Support getting changes of non-HEAD branches

scm.py

Index: scm.py
diff --git a/scm.py b/scm.py
index 7d7554907177b51731c95c3ae180778fe37ede8b..8edb39d6c0b1b19fa88fbff00983d6c3e4d372c0 100644
--- a/scm.py
+++ b/scm.py
@@ -122,7 +122,7 @@ class GIT(object):
     return output.strip() if strip_out else output
 
   @staticmethod
-  def CaptureStatus(files, cwd, upstream_branch):
+  def CaptureStatus(files, cwd, upstream_branch, local_branch='HEAD'):
     """Returns git status.
 
     @files can be a string (one file) or a list of files.
@@ -133,7 +133,7 @@ class GIT(object):
       if upstream_branch is None:
         raise gclient_utils.Error('Cannot determine upstream branch')
     command = ['diff', '--name-status', '--no-renames',
-               '-r', '%s...' % upstream_branch]
+               '-r', '%s...%s' % (upstream_branch, local_branch)]
     if not files:
       pass
     elif isinstance(files, basestring):