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

mojo/public/cpp/environment/tests/logger_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.
 
 #include <mojo/environment/logger.h>
 
+#include "gtest/gtest.h"
 #include "mojo/public/cpp/environment/environment.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace {
 
 std::vector<std::string> g_log_msgs;
 const MojoLogger kTestLogger = {
     [](MojoLogLevel log_level,
        const char* source_file,
        uint32_t source_line,
        const char* message) { g_log_msgs.push_back(message); },
@@ skipping 90 matching lines @@
 
   // This should restore the default logger.
   Environment::SetDefaultLogger(nullptr);
 
   EXPECT_NE(&kTestLogger, Environment::GetDefaultLogger());
   EXPECT_NE(nullptr, Environment::GetDefaultLogger());
 }
 
 }  // namespace
 }  // namespace mojo