Introduce a layering in the invalidation component as public and impl

components/invalidation/invalidation_test_util.h

Index: components/invalidation/invalidation_test_util.h
diff --git a/components/invalidation/invalidation_test_util.h b/components/invalidation/invalidation_test_util.h
deleted file mode 100644
index c0394949d4950c00d2662337dad9a2ba0af582d4..0000000000000000000000000000000000000000
--- a/components/invalidation/invalidation_test_util.h
+++ /dev/null
@@ -1,26 +0,0 @@
-// 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.
-
-#ifndef COMPONENTS_INVALIDATION_INVALIDATION_TEST_UTIL_H_
-#define COMPONENTS_INVALIDATION_INVALIDATION_TEST_UTIL_H_
-
-#include <iosfwd>
-
-#include "testing/gmock/include/gmock/gmock.h"
-
-namespace syncer {
-
-class AckHandle;
-class Invalidation;
-
-void PrintTo(const AckHandle& ack_handle, ::std::ostream* os);
-::testing::Matcher<const AckHandle&> Eq(const AckHandle& expected);
-
-void PrintTo(const Invalidation& invalidation, ::std::ostream* os);
-
-::testing::Matcher<const Invalidation&> Eq(const Invalidation& expected);
-
-}  // namespace syncer
-
-#endif  // COMPONENTS_INVALIDATION_INVALIDATION_TEST_UTIL_H_