Add mus::mojom::ChannelHandle for passing IPC::ChannelHandle via mojo IPC.

testing/buildbot/gn_isolate_map.pyl

 ## Copyright 2015 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.
 
 # gn_isolate_map.pyl - A mapping of Ninja build target names to GN labels and
 # test type classifications for the tests that are run on the bots.
 #
 # This mapping is used by MB so that we can uniformly refer to test binaries
 # by their Ninja target names in the recipes and not need to worry about how
 # they are referred to in GN or GYP specifically (the GYP target name is pretty
@@ skipping 391 matching lines @@
     "type": "unknown",
   },
   "message_center_unittests": {
     "label": "//ui/message_center:message_center_unittests",
     "type": "console_test_launcher",
   },
   "mash_unittests": {
     "label": "//mash:mash_unittests",
     "type": "unknown",
   },
+  "mus_gpu_unittests": {
+    "label": "//components/mus/gpu:mus_gpu_unittests",
+    "type": "console_test_launcher",
+  },
   "mus_ws_unittests": {
     "label": "//components/mus/ws:mus_ws_unittests",
     "type": "windowed_test_launcher",
   },
   "nacl_loader_unittests": {
     "label": "//components/nacl/loader:nacl_loader_unittests",
     "type": "raw",
     "args": [],
   },
   "net_unittests": {
@@ skipping 148 matching lines @@
   },
   "wm_unittests": {
     "label": "//ui/wm:wm_unittests",
     "type": "windowed_test_launcher",
   },
   "wtf_unittests": {
     "label": "//third_party/WebKit/Source/wtf:wtf_unittests",
     "type": "console_test_launcher",
   },
 }