Changing mb.py to use autoninja

This cl changes the build step to use autoninja rather than ninja.
It will correctly detect and switch between autoninja and
autoninja.bat depending on the os.

Change-Id: If1ada0e440d4b5baed71e0eccbb16f2a9a532a45
Reviewed-on: https://chromium-review.googlesource.com/986872Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Mike Meade <mmeade@google.com>
Cr-Commit-Position: refs/heads/master@{#547308}

tools/mb/mb.py

@@ -1304,7 +1304,11 @@ class MetaBuildWrapper(object):
 
   def Build(self, target):
     build_dir = self.ToSrcRelPath(self.args.path)
-    ninja_cmd = ['ninja', '-C', build_dir]
+    if self.platform == 'win32':
+      # On Windows use the batch script since there is no exe
+      ninja_cmd = ['autoninja.bat', '-C', build_dir]
+    else:
+      ninja_cmd = ['autoninja', '-C', build_dir]
     if self.args.jobs:
       ninja_cmd.extend(['-j', '%d' % self.args.jobs])
     ninja_cmd.append(target)

tools/mb/mb_unittest.py

@@ -7,7 +7,6 @@
 
 import json
 import StringIO
-import os
 import sys
 import unittest
 
@@ -648,6 +647,38 @@ class UnitTest(unittest.TestCase):
                     '[bucket "master.tryserver.chromium.mac"]\n'
                     '\tbuilder = try_builder2\n'))
 
+  def test_build_command_unix(self):
+    files = {
+      '/fake_src/out/Default/toolchain.ninja': '',
+      '/fake_src/testing/buildbot/gn_isolate_map.pyl': (
+          '{"base_unittests": {'
+          '  "label": "//base:base_unittests",'
+          '  "type": "raw",'
+          '  "args": [],'
+          '}}\n')
+    }
+
+    mbw = self.fake_mbw(files)
+    self.check(['run', '//out/Default', 'base_unittests'], mbw=mbw, ret=0)
+    self.assertIn(['autoninja', '-C', 'out/Default', 'base_unittests'],
+                  mbw.calls)
+
+  def test_build_command_windows(self):
+    files = {
+      'c:\\fake_src\\out\\Default\\toolchain.ninja': '',
+      'c:\\fake_src\\testing\\buildbot\\gn_isolate_map.pyl': (
+          '{"base_unittests": {'
+          '  "label": "//base:base_unittests",'
+          '  "type": "raw",'
+          '  "args": [],'
+          '}}\n')
+    }
+
+    mbw = self.fake_mbw(files, True)
+    self.check(['run', '//out/Default', 'base_unittests'], mbw=mbw, ret=0)
+    self.assertIn(['autoninja.bat', '-C', 'out\\Default', 'base_unittests'],
+                  mbw.calls)
+
 
 if __name__ == '__main__':
   unittest.main()