tools: Make mass-rename.py print progress as it works

tools/git/mass-rename.py

 #!/usr/bin/env python
 # Copyright 2013 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.
 
 """
 mass-rename: update source files (gyp lists, #includes) to reflect
 a rename.  Expects "git diff --cached -M" to list a bunch of renames.
 
 To use:
@@ skipping 10 matching lines @@
 
 BASE_DIR = os.path.abspath(os.path.dirname(__file__))
 
 
 def main():
   popen = subprocess.Popen('git diff --cached --raw -M',
                            shell=True, stdout=subprocess.PIPE)
   out, _ = popen.communicate()
   if popen.returncode != 0:
     return 1
-  for line in out.splitlines():
+  lines = out.splitlines()
+  for item, line in enumerate(lines, 1):
+    # Print progress
+    print '[%d/%d]' % (item, len(lines)),
+
     parts = line.split('\t')
     if len(parts) != 3:
       print 'Skipping: %s -- not a rename?' % parts
       continue
     attrs, fro, to = parts
     if attrs.split()[4].startswith('R'):
+      print 'Moving: %s' % fro
       subprocess.check_call([
         sys.executable,
         os.path.join(BASE_DIR, 'move_source_file.py'),
         '--already_moved',
         '--no_error_for_non_source_file',
         fro, to])
     else:
       print 'Skipping: %s -- not a rename?' % fro
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())