Use luci-go isolate client in mb.py

Because go's "check" subcommand doesn't generate isolated file, the '-s' flag is dropped. This is fine because Go isolate doesn't consume isolated file at all. More details in crbug.com/1059668.

#Benchmark

Benchmark is done using the "archive" subcommand. Note that the first invocation will upload to isolate-server, which we want to *exclude*. So the results were taken from the second invocation.

##blink_web_tests:

* PY: 1m15s~1m40s (python tools/swarming_client/isolate.py archive -i out/Release/blink_web_tests.isolate -s out/Release/blink_web_tests.isolated -I https://isolateserver.appspot.com)
* GO: ~8s (tools/luci-go/isolate archive -i out/Release/blink_web_tests.isolate -s out/Release/blink_web_tests.isolated -I https://isolateserver.appspot.com)

##browsers_tests:

* PY: 31s
* GO: 3s

Bug: 1059167
Change-Id: Idffb6c33e2482c2829f54c56e753623f26997a10
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2094482
Commit-Queue: Ye Kuang <yekuang@google.com>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749557}

tools/mb/mb.py

@@ -99,6 +99,8 @@ class MetaBuildWrapper(object):
     self.masters = {}
     self.buckets = {}
     self.mixins = {}
+    self.isolate_exe = 'isolate.exe' if self.platform.startswith(
+        'win') else 'isolate'
 
   def Main(self, args):
     self.ParseArgs(args)
@@ -564,11 +566,10 @@ class MetaBuildWrapper(object):
     try:
       zip_dir = self.TempDir()
       remap_cmd = [
-          self.executable,
-          self.PathJoin(self.chromium_src_dir, 'tools', 'swarming_client',
-                        'isolate.py'), 'remap', '--collapse_symlinks', '-s',
-          self.PathJoin(self.args.path, self.args.target + '.isolated'), '-o',
-          zip_dir
+          self.PathJoin(self.chromium_src_dir, 'tools', 'luci-go',
+                        self.isolate_exe), 'remap', '-i',
+          self.PathJoin(self.args.path, self.args.target + '.isolate'),
+          '-outdir', zip_dir
       ]
       self.Run(remap_cmd)
 
@@ -647,12 +648,15 @@ class MetaBuildWrapper(object):
       dimensions += ['-d', k, v]
 
     cmd = [
-        self.executable,
-        self.PathJoin('tools', 'swarming_client', 'isolate.py'),
+        self.PathJoin(self.chromium_src_dir, 'tools', 'luci-go',
+                      self.isolate_exe),
         'archive',
-        '-s', self.ToSrcRelPath('%s/%s.isolated' % (build_dir, target)),
-        '-I', isolate_server,
-        '--namespace', namespace,
+        '-s',
+        self.ToSrcRelPath('%s/%s.isolated' % (build_dir, target)),
+        '-I',
+        isolate_server,
+        '-namespace',
+        namespace,
     ]
 
     # Talking to the isolateserver may fail because we're not logged in.
@@ -694,11 +698,11 @@ class MetaBuildWrapper(object):
 
   def _RunLocallyIsolated(self, build_dir, target):
     cmd = [
-        self.executable,
-        self.PathJoin('tools', 'swarming_client', 'isolate.py'),
+        self.PathJoin(self.chromium_src_dir, 'tools', 'luci-go',
+                      self.isolate_exe),
         'run',
-        '-s',
-        self.ToSrcRelPath('%s/%s.isolated' % (build_dir, target)),
+        '-i',
+        self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target)),
     ]
     if self.args.extra_args:
       cmd += ['--'] + self.args.extra_args
@@ -1287,13 +1291,12 @@ class MetaBuildWrapper(object):
       return ret
 
     ret, _, _ = self.Run([
-        self.executable,
-        self.PathJoin('tools', 'swarming_client', 'isolate.py'),
+        self.PathJoin(self.chromium_src_dir, 'tools', 'luci-go',
+                      self.isolate_exe),
         'check',
         '-i',
         self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target)),
-        '-s',
-        self.ToSrcRelPath('%s/%s.isolated' % (build_dir, target))],
+    ],
                          buffer_output=False)
 
     return ret

tools/mb/mb_unittest.py

@@ -842,7 +842,7 @@ class UnitTest(unittest.TestCase):
     }
 
     def run_stub(cmd, **_kwargs):
-      if 'isolate.py' in cmd[1]:
+      if os.path.join('tools', 'luci-go', 'isolate') in cmd[0]:
         return 0, 'fake_hash base_unittests', ''
       else:
         return 0, '', ''