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

mojo/public/cpp/system/tests/macros_unittest.cc

 // 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.
 
 // This file tests the C++ Mojo system macros and consists of "positive" tests,
 // i.e., those verifying that things work (without compile errors, or even
 // warnings if warnings are treated as errors).
 // TODO(vtl): Fix no-compile tests (which are all disabled; crbug.com/105388)
 // and write some "negative" tests.
 
 #include "mojo/public/cpp/system/macros.h"
 
 #include <assert.h>
 #include <stdint.h>
 #include <stdlib.h>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "gtest/gtest.h"
 
 namespace mojo {
 namespace {
 
 // Note: MSVS is very strict (and arguably buggy) about warnings for classes
 // defined in a local scope, so define these globally.
 struct TestOverrideBaseClass {
   virtual ~TestOverrideBaseClass() {}
   virtual void ToBeOverridden() {}
   virtual void AlsoToBeOverridden() = 0;
@@ skipping 104 matching lines @@
 int ReturnsIntYouMustUse() {
   return 123;
 }
 
 TEST(MacrosTest, IgnoreResult) {
   ignore_result(ReturnsIntYouMustUse());
 }
 
 }  // namespace
 }  // namespace mojo