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

mojo/public/cpp/bindings/tests/type_conversion_unittest.cc

 // Copyright 2013 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 "gtest/gtest.h"
 #include "mojo/public/cpp/environment/environment.h"
 #include "mojo/public/interfaces/bindings/tests/test_structs.mojom.h"
-#include "testing/gtest/include/gtest/gtest.h"
 
 namespace mojo {
 namespace {
 
 struct RedmondRect {
   int32_t left;
   int32_t top;
   int32_t right;
   int32_t bottom;
 };
@@ skipping 178 matching lines @@
     EXPECT_EQ(redmond_region.rects[i].left, redmond_region2.rects[i].left);
     EXPECT_EQ(redmond_region.rects[i].top, redmond_region2.rects[i].top);
     EXPECT_EQ(redmond_region.rects[i].right, redmond_region2.rects[i].right);
     EXPECT_EQ(redmond_region.rects[i].bottom, redmond_region2.rects[i].bottom);
   }
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace mojo