Generalize specifying revisions for VR bisect script

Generalizes the ability to specify specific revisions for other
repositories when using the VR bisect script. Previously, this was only
available as an option for specifying a clank revision, but can now be
used if some other repository is causing compile errors in the
regression range.

Change-Id: Ieb5045b21989541102a1f57bcf17e0b0e18f710c
Reviewed-on: https://chromium-review.googlesource.com/956562
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541944}

chrome/test/vr/auto_bisect.py

@@ -66,10 +66,22 @@ def ParseArgsAndAssertValid():
                       help='The value of the metric at the bad revision. If '
                            'not defined, an extra test iteration will be run '
                            'to determine the value')
-  parser.add_argument('--clank-revision',
-                      help='The Clank revision to sync to during the bisect. '
-                           'Only necessary if the revision on ToT is not '
-                           'compatible with the revision range of the bisect')
+  def comma_separated(arg):
+    split_arg = arg.split(',')
+    if len(split_arg) != 2:
+      raise argparse.ArgumentError(
+          'Expected two comma-separated strings but '
+          'received %d' % len(split_arg))
+    return {split_arg[0]: split_arg[1]}
+  parser.add_argument('--checkout-override', action='append',
+                      type=comma_separated, dest='checkout_overrides',
+                      help='A comma-separated path/revision key/value pair. '
+                           'Each git checkout at the specified path will be '
+                           'synced to the specified revision after the normal '
+                           'sync. For example, passing '
+                           'third_party/android_ndk,abcdefg would cause the '
+                           'checkout in //third_party/android_ndk to be synced '
+                           'to revision abcdefg.')
   parser.add_argument('--reset-before-sync', action='store_true',
                       default=False,
                       help='When set, runs "git reset --hard HEAD" before '
@@ -82,14 +94,7 @@ def ParseArgsAndAssertValid():
                       help='The swarming server to trigger the test on')
   parser.add_argument('--isolate-server', required=True,
                       help='The isolate server to upload the test to')
-  def dimension(arg):
-    split_arg = arg.split(',')
-    if len(split_arg) != 2:
-      raise argparse.ArgumentError(
-          'Expected two comma-separated strings for --dimension, '
-          'received %d' % len(split_arg))
-    return {split_arg[0]: split_arg[1]}
-  parser.add_argument('--dimension', action='append', type=dimension,
+  parser.add_argument('--dimension', action='append', type=comma_separated,
                       default=[], dest='dimensions',
                       help='A comma-separated swarming dimension key/value '
                            'pair. At least one must be provided.')
@@ -151,6 +156,10 @@ def VerifyInput(args, unknown_args):
   else:
     print 'Changing from %f at %s to %f at %s' % (args.good_value,
         args.good_revision, args.bad_value, args.bad_revision)
+  if args.checkout_overrides:
+    for pair in args.checkout_overrides:
+      for key, val in pair.iteritems():
+        print '%s will be synced to revision %s' % (key, val)
   print '======'
   print 'The test target %s will be built to %s' % (args.build_target,
                                                     args.build_output_dir)
@@ -363,10 +372,14 @@ def SyncAndBuild(args, unknown_args, revision):
         'If these changes are actually yours, please commit or stash them. If '
         'they are not, remove them and try again. If the issue persists, try '
         'running with --reset-before-sync')
-  if args.clank_revision:
-    os.chdir('clank')
-    subprocess.check_output(['git', 'checkout', args.clank_revision])
-    os.chdir('..')
+
+  # Checkout any specified revisions.
+  cwd = os.getcwd()
+  for override in args.checkout_overrides:
+    for repo, rev in override.iteritems():
+      os.chdir(repo)
+      subprocess.check_output(['git', 'checkout', rev])
+      os.chdir(cwd)
   print 'Building'
   subprocess.check_output(['ninja', '-C', args.build_output_dir,
                            '-j', str(args.parallel_jobs),