Move the test template to //testing/test.gni (part 2)

extensions/BUILD.gn

 # Copyright 2014 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.
 
+import("//testing/rules.gni")
 import("//tools/grit/grit_rule.gni")
 import("//tools/grit/repack.gni")
 
 assert(enable_extensions)
 
 # GYP version: extensions/extensions_resources.gyp:extensions_resources
 group("extensions_resources") {
   deps = [
     ":extensions_browser_resources",
     ":extensions_renderer_resources",
@@ skipping 260 matching lines @@
       "//testing/gmock",
       "//testing/gtest",
       "//third_party/leveldatabase",
     ]
 
     if (is_win) {
       deps += [ "//base/allocator" ]
     }
   }
 }