Add support for parallel runs

ct/isolates/build_repo.isolate

 # Copyright (c) 2016 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.
 
 {
   'includes': [
     'py.isolate',
   ],
   'conditions': [
     ['OS=="linux"', {
       'variables': {
         'files': [
-          '../../../../../bin/create_pagesets',
+          '../../../../../bin/build_repo',
         ],
         'command': [
-          '../../../../../bin/create_pagesets',
+          '../../../../../bin/build_repo',
           '-logtostderr',
-          '--start_range=<(START_RANGE)',
-          '--num=<(NUM)',
-          '--pageset_type=<(PAGESET_TYPE)',
+          '--run_id=<(RUN_ID)',
+          '--repo=<(REPO)',
+          '--hashes=<(HASHES)',
+          '--patches=<(PATCHES)',
+          '--single_build=<(SINGLE_BUILD)',
+          '--target_platform=<(TARGET_PLATFORM)',
+          '--out=${ISOLATED_OUTDIR}',
         ],
       },
     }],
   ]
 }