mojo/public: Include gtest.h as "gtest/gtest.h", instead of via "absolute" path.

mojo/public/cpp/environment/tests/run_loop_async_wait_perftest.cc

 // Copyright 2016 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 file has perf tests for async waits using |mojo::RunLoop| (i.e., the
 // "standalone" |Environment|).
 
 #include <stdio.h>
 
+#include "gtest/gtest.h"
 #include "mojo/public/c/tests/environment/async_waiter_perftest_helpers.h"
 #include "mojo/public/cpp/environment/environment.h"
 #include "mojo/public/cpp/test_support/test_support.h"
 #include "mojo/public/cpp/utility/run_loop.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace {
 
 constexpr MojoTimeTicks kPerftestTimeMicroseconds = 3 * 1000000;
 
 TEST(RunLoopAsyncWaitPerftest, SingleThreaded) {
   for (uint32_t num_handles = 1u; num_handles <= 10000u; num_handles *= 10u) {
     RunLoop run_loop;
 
@@ skipping 13 matching lines @@
                     (static_cast<double>(end_time - start_time) / 1000000.0);
     char sub_test_name[100] = {};
     sprintf(sub_test_name, "%u", static_cast<unsigned>(num_handles));
     test::LogPerfResult("RunLoopAsyncWaitPerftest.SingleThreaded",
                         sub_test_name, result, "callbacks/second");
   }
 }
 
 }  // namespace
 }  // namespace mojo