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

mojo/public/cpp/environment/tests/logging_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 <stdlib.h>
 
 #include <sstream>
 #include <string>
 
+#include "gtest/gtest.h"
 #include "mojo/public/cpp/environment/environment.h"
 #include "mojo/public/cpp/environment/logging.h"
 #include "mojo/public/cpp/system/macros.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace {
 
 // The current logging system strips the path, so we need our filename.
 const char kOurFilename[] = "logging_unittest.cc";
 
 class PtrToMemberHelper {
  public:
   int member;
@@ skipping 487 matching lines @@
   ResetMockLogger();
 
   // Also try to make sure that we parenthesize the condition properly.
   bool x = true;
   MOJO_DCHECK(false || x) << "hello";
   EXPECT_FALSE(log_message_was_called());
 }
 
 }  // namespace
 }  // namespace mojo