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

mojo/public/c/tests/system/data_pipe_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 data pipe API (the functions declared in
 // mojo/public/c/include/mojo/system/data_pipe.h).
 
 #include <mojo/system/data_pipe.h>
 
 #include <mojo/result.h>
 #include <mojo/system/handle.h>
 #include <mojo/system/wait.h>
 #include <string.h>
 
-#include "testing/gtest/include/gtest/gtest.h"
+#include "gtest/gtest.h"
 
 namespace {
 
 const MojoHandleRights kDefaultDataPipeProducerHandleRights =
     MOJO_HANDLE_RIGHT_TRANSFER | MOJO_HANDLE_RIGHT_WRITE |
     MOJO_HANDLE_RIGHT_GET_OPTIONS | MOJO_HANDLE_RIGHT_SET_OPTIONS;
 const MojoHandleRights kDefaultDataPipeConsumerHandleRights =
     MOJO_HANDLE_RIGHT_TRANSFER | MOJO_HANDLE_RIGHT_READ |
     MOJO_HANDLE_RIGHT_GET_OPTIONS | MOJO_HANDLE_RIGHT_SET_OPTIONS;
 
@@ skipping 409 matching lines @@
   EXPECT_EQ(MOJO_RESULT_OK,
             MojoWait(hc, MOJO_HANDLE_SIGNAL_READ_THRESHOLD, 0, nullptr));
 
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(hp));
   EXPECT_EQ(MOJO_RESULT_OK, MojoClose(hc));
 }
 
 // TODO(vtl): Add multi-threaded tests.
 
 }  // namespace