Move gn _run target generation into test(). (RELAND)

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 168 matching lines @@
       } else {
         deps = []
       }
       deps += [
         # All shared libraries must have the sanitizer deps to properly link in
         # asan mode (this target will be empty in other cases).
         "//build/config/sanitizers:deps",
       ]
     }
   } else {
+    main_target_name = target_name
+
     executable(target_name) {
       forward_variables_from(invoker, "*")
 
       testonly = true
 
       if (!defined(invoker.deps)) {
         deps = []
       }
       deps += [
         # All shared libraries must have the sanitizer deps to properly link in
         # asan mode (this target will be empty in other cases).
         "//build/config/sanitizers:deps",
 
         # Give tests the default manifest on Windows (a no-op elsewhere).
         "//build/win:default_exe_manifest",
       ]
     }
+
+    # TODO(GYP): Delete this after we've converted everything to GN.
+    # The _run targets exist only for compatibility with GYP.
+    group("${target_name}_run") {
+      testonly = true
+      deps = [
+        ":$main_target_name",
+      ]
+    }
   }
 }