Add support to check if the url has changed for a git dep and create a new clone.

gclient_scm.py

 # Copyright (c) 2010 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.
 
 """Gclient-specific SCM-specific operations."""
 
 import logging
 import os
 import posixpath
 import re
@@ skipping 168 matching lines @@
     rev_str = ' at %s' % revision
     files = []
 
     printed_path = False
     verbose = []
     if options.verbose:
       print('\n_____ %s%s' % (self.relpath, rev_str))
       verbose = ['--verbose']
       printed_path = True
 
+    # See if the url has changed
+    current_url = self._Capture(['config', 'remote.origin.url'])
+    if current_url != url:
+      print('_____ switching %s to a new upstream' % self.relpath)
+      # Make sure it's clean
+      self._CheckClean(rev_str)
+      # Switch over to the new upstream
+      self._Run(['remote', 'set-url', 'origin', url], options)
+      quiet = []
+      if not options.verbose:
+        quiet = ['--quiet']
+      self._Run(['fetch', 'origin', '--prune'] + quiet, options)
+      self._Run(['reset', '--hard', 'origin/master'] + quiet, options)
+      files = self._Capture(['ls-files']).splitlines()
+      file_list.extend([os.path.join(self.checkout_path, f) for f in files])
+      return
+
     if revision.startswith('refs/heads/'):
       rev_type = "branch"
     elif revision.startswith('origin/'):
       # For compatability with old naming, translate 'origin' to 'refs/heads'
       revision = revision.replace('origin/', 'refs/heads/')
       rev_type = "branch"
     else:
       # hash is also a tag, only make a distinction at checkout
       rev_type = "hash"
 
     if not os.path.exists(self.checkout_path):
       self._Clone(revision, url, options)
-      files = self._Capture(['ls-files']).split()
+      files = self._Capture(['ls-files']).splitlines()
       file_list.extend([os.path.join(self.checkout_path, f) for f in files])
       if not verbose:
         # Make the output a little prettier. It's nice to have some whitespace
         # between projects when cloning.
         print('')
       return
 
     if not os.path.exists(os.path.join(self.checkout_path, '.git')):
       raise gclient_utils.Error('\n____ %s%s\n'
                                 '\tPath is not a git repo. No .git dir.\n'
@@ skipping 692 matching lines @@
 
     This method returns a new list to be used as a command."""
     new_command = command[:]
     if revision:
       new_command.extend(['--revision', str(revision).strip()])
     # --force was added to 'svn update' in svn 1.5.
     if ((options.force or options.manually_grab_svn_rev) and
         scm.SVN.AssertVersion("1.5")[0]):
       new_command.append('--force')
     return new_command