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

mojo/public/cpp/bindings/tests/iterator_util_unittest.cc

 // 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.
 
 #include <algorithm>
 
+#include "gtest/gtest.h"
 #include "mojo/public/cpp/bindings/lib/iterator_util.h"
 #include "mojo/public/cpp/bindings/map.h"
 #include "mojo/public/cpp/bindings/tests/iterator_test_util.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace test {
 
 using internal::MapKeyIterator;
 using internal::MapValueIterator;
 
 TEST(MapIteratorTest, KeyIterator) {
   Map<int, int> my_map;
   my_map[1] = 2;
@@ skipping 59 matching lines @@
     expected_vals.push_back(2);
     expected_vals.push_back(4);
     expected_vals.push_back(6);
     ExpectBidiMutableIteratorConcept(map_value_iter.begin(),
                                      map_value_iter.end(), expected_vals);
   }
 }
 
 }  // namespace test
 }  // namespace mojo