Convert Mojo tests to use swarming.

BUILD.gn

 # Copyright (c) 2013 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 620 matching lines @@
       "//third_party/openh264:processing",
     ]
   }
 }
 
 # This group contains all the targets needed to run mojo's apptest_runner.
 group("mojo_apptests") {
   testonly = true
 
   deps = []
+  data_deps = []
+  data = []
 
   if (is_win || is_linux) {
-    deps += [
-      "//components/resource_provider:resource_provider_unittests",
-      "//mash:mash_unittests",
-      "//media/mojo/services:tests",
-      "//ui/views/mus:tests",
+    deps += [ "//services/shell/standalone" ]
+    data_deps = [
+      "//media/mojo/services:media_apptests",
+    ]
+    if (is_linux) {
+      data_deps += [ "//tools/xdisplaycheck" ]
+    }
+    data += [
+      "//mojo/tools/apptest_runner.py",
+      "//mojo/tools/data/apptests",
+      "//mojo/tools/mopy/",
+      "//testing/xvfb.py",
+      "//tools/swarming_client/utils/subprocess42.py",
     ]
   }
 }
 
+group("mojo_apptests_run") {
+  testonly = true
+  deps = [
+    ":mojo_apptests",
+  ]
+}
+
 group("gn_only") {
   testonly = true
 
   deps = []
 
   if (!is_ios) {
     deps += [ "//mojo/common:mojo_common_perftests" ]
   }
 
   if (!is_android && !is_ios) {
@@ skipping 308 matching lines @@
   assert(target_name != "")  # Mark as used.
   sources = invoker.actual_sources
   assert(
       sources == invoker.actual_sources,
       "Do not use a platform name in your output directory (found \"$root_build_dir\"). http://crbug.com/548283")
 }
 
 assert_valid_out_dir("_unused") {
   actual_sources = [ "$root_build_dir/foo" ]
 }