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

mojo/public/cpp/bindings/tests/router_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 <string.h>
 
+#include "gtest/gtest.h"
 #include "mojo/public/cpp/bindings/lib/message_builder.h"
 #include "mojo/public/cpp/bindings/lib/router.h"
 #include "mojo/public/cpp/bindings/tests/message_queue.h"
 #include "mojo/public/cpp/system/macros.h"
 #include "mojo/public/cpp/utility/run_loop.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace test {
 namespace {
 
 void AllocRequestMessage(uint32_t name, const char* text, Message* message) {
   size_t payload_size = strlen(text) + 1;  // Plus null terminator.
   RequestMessageBuilder builder(name, payload_size);
   memcpy(builder.buffer()->Allocate(payload_size), text, payload_size);
 
@@ skipping 429 matching lines @@
     EXPECT_TRUE(generator.has_responder());
   }
 
   EXPECT_FALSE(generator.responder_is_valid());
   generator.CompleteWithResponse();  // This should end up doing nothing.
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace mojo