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

mojo/public/c/tests/system/handle_unittest.cc

 // Copyright 2016 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 handle API (the functions declared in
 // mojo/public/c/include/mojo/system/handle.h). Note: The functionality of these
 // APIs for specific types of handles are tested with the APIs for those types
 // of handles.
 
 #include <mojo/system/handle.h>
 
 #include <mojo/result.h>
 #include <mojo/system/message_pipe.h>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "gtest/gtest.h"
 
 namespace {
 
 const MojoHandleRights kDefaultMessagePipeHandleRights =
     MOJO_HANDLE_RIGHT_TRANSFER | MOJO_HANDLE_RIGHT_READ |
     MOJO_HANDLE_RIGHT_WRITE | MOJO_HANDLE_RIGHT_GET_OPTIONS |
     MOJO_HANDLE_RIGHT_SET_OPTIONS;
 
 TEST(HandleTest, InvalidHandle) {
   // MojoClose:
@@ skipping 83 matching lines @@
   // Make sure that the rights are actually correctly enforced.
   EXPECT_EQ(
       MOJO_RESULT_PERMISSION_DENIED,
       MojoWriteMessage(h0r1, &x, 1u, nullptr, 0, MOJO_WRITE_MESSAGE_FLAG_NONE));
 
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(h0r1));
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(h1));
 }
 
 }  // namespace