[android] Write a runner script to the top-level output dir for gtests.

testing/test.gni

 # 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.
 
 # ==============================================================================
 # TEST SETUP
 # ==============================================================================
 
 if (is_android) {
   import("//build/config/android/config.gni")
@@ skipping 172 matching lines @@
           executable_dist_dir = "$root_out_dir/$_dist_target"
         } else {
           apk_target = ":$_apk_target"
         }
         test_name = _output_name
         test_type = "gtest"
         test_suite = _output_name
       }
     }
 
-    group(target_name) {
-      testonly = true
-      if (_incremental_apk_only) {
-        deps = [
-          ":${target_name}_incremental",
+    test_runner_script(target_name) {
+      forward_variables_from(invoker,
+                             _wrapper_script_vars + [
+                                   "data",
+                                   "data_deps",
+                                   "deps",
+                                   "public_deps",
+                                 ])
+
+      if (_use_raw_android_executable) {
+        executable_dist_dir = "$root_out_dir/$_dist_target"
+        deps += [
+          ":$_dist_target",
+          ":$_test_runner_target",
         ]
       } else {
-        deps = [
-          ":$_test_runner_target",
-        ]
-        if (_use_raw_android_executable) {
-          deps += [ ":$_dist_target" ]
+        apk_target = ":$_apk_target"
+        deps += [ ":$_apk_target" ]
+        if (_incremental_apk_only) {
+          deps += [ ":${target_name}_incremental" ]
         } else {
-          deps += [ ":$_apk_target" ]
+          deps += [ ":$_test_runner_target" ]
         }
       }
+      generated_script = "$root_build_dir/$_output_name"
+      incremental_install = _incremental_apk_only
+      test_name = _output_name
+      test_suite = _output_name
+      test_type = "gtest"
     }
 
     # TODO(GYP_GONE): Delete this after we've converted everything to GN.
     # The _run targets exist only for compatibility w/ GYP.
     group("${target_name}_apk_run") {
       testonly = true
       deps = [
         ":${invoker.target_name}",
       ]
     }
@@ skipping 68 matching lines @@
 }
 
 # Test defaults.
 set_defaults("test") {
   if (is_android) {
     configs = default_shared_library_configs
   } else {
     configs = default_executable_configs
   }
 }