Add --upstream option to gclient to scrape git checkouts back to upstream state.

This will be used on the bots when calling apply_patch, which commits to git
repos.

R=dpranke@chromium.org,szager@chromium.org
BUG=

Review URL: https://chromiumcodereview.appspot.com/18006002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@209040 0039d316-1c4b-4281-b951-d872f2087c98

gclient.py

@@ -1541,6 +1541,8 @@ def CMDsync(parser, args):
   parser.add_option('-m', '--manually_grab_svn_rev', action='store_true',
                     help='Skip svn up whenever possible by requesting '
                          'actual HEAD revision from the repository')
+  parser.add_option('--upstream', action='store_true',
+                    help='Make repo state match upstream branch.')
   (options, args) = parser.parse_args(args)
   client = GClient.LoadCurrentConfig(options)
 
@@ -1590,6 +1592,8 @@ def CMDrevert(parser, args):
                          'references')
   parser.add_option('-n', '--nohooks', action='store_true',
                     help='don\'t run hooks after the revert is complete')
+  parser.add_option('--upstream', action='store_true',
+                    help='Make repo state match upstream branch.')
   (options, args) = parser.parse_args(args)
   # --force is implied.
   options.force = True

gclient_scm.py

@@ -430,7 +430,10 @@ class GitWrapper(SCMWrapper):
 
     # This is a big hammer, debatable if it should even be here...
     if options.force or options.reset:
-      self._Run(['reset', '--hard', 'HEAD'], options)
+      target = 'HEAD'
+      if options.upstream and upstream_branch:
+        target = upstream_branch
+      self._Run(['reset', '--hard', target], options)
 
     if current_type == 'detached':
       # case 0
@@ -578,6 +581,10 @@ class GitWrapper(SCMWrapper):
       return self.update(options, [], file_list)
 
     default_rev = "refs/heads/master"
+    if options.upstream:
+      if self._GetCurrentBranch():
+        upstream_branch = scm.GIT.GetUpstreamBranch(self.checkout_path)
+        default_rev = upstream_branch or default_rev
     _, deps_revision = gclient_utils.SplitUrlRevision(self.url)
     if not deps_revision:
       deps_revision = default_rev

tests/gclient_scm_test.py

@@ -684,6 +684,7 @@ class BaseGitWrapperTestCase(GCBaseTestCase, StdoutCheck, TestCaseUtils,
       self.force = False
       self.reset = False
       self.nohooks = False
+      self.upstream = False
       self.merge = False
       self.jobs = 1
       self.delete_unversioned_trees = False