[Android] Generate scripts at build time to run android tests.

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
 # ==============================================================================
 
 # Define a test as an executable (or apk on Android) with the "testonly" flag
 # set.
@@ skipping 113 matching lines @@
         ":$library_name",
       ]
       if (defined(invoker.apk_deps)) {
         deps += invoker.apk_deps
       }
       if (defined(invoker.apk_asset_location)) {
         asset_location = invoker.apk_asset_location
       }
     }
 
+    test_name = main_target_name
+    if (defined(invoker.output_name)) {
+      test_name = invoker.output_name
+    }
+    test_runner_script_name = "${test_name}__test_runner_script"
+    test_runner_script(test_runner_script_name) {
+      test_type = "gtest"
+      test_suite = test_name
+      if (defined(invoker.isolate_file)) {
+        isolate_file = invoker.isolate_file
+      }
+    }
+
     group(target_name) {
       testonly = true
-
+      datadeps = [
+        ":$test_runner_script_name",
+      ]
       deps = [
         ":$library_name",
         ":$apk_name",
       ]
     }
   } else {
     executable(target_name) {
       # See above.
       configs = []  # Prevent list overwriting warning.
       configs = invoker.configs
@@ skipping 84 matching lines @@
       }
       if (defined(invoker.sources)) {
         sources = invoker.sources
       }
       if (defined(invoker.visibility)) {
         visibility = invoker.visibility
       }
     }
   }
 }