Introduce a layering in the invalidation component as public and impl

components/invalidation/impl/mock_ack_handler.h

Index: components/invalidation/impl/mock_ack_handler.h
diff --git a/components/invalidation/mock_ack_handler.h b/components/invalidation/impl/mock_ack_handler.h
similarity index 87%
rename from components/invalidation/mock_ack_handler.h
rename to components/invalidation/impl/mock_ack_handler.h
index 8afcb4fa8d01de4fa0a151aaa349023123eb0e7d..1e5effc3cbab494971b854d70e36b41b8db11030 100644
--- a/components/invalidation/mock_ack_handler.h
+++ b/components/invalidation/impl/mock_ack_handler.h
@@ -2,17 +2,17 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef COMPONENTS_INVALIDATION_MOCK_ACK_HANDLER_H_
-#define COMPONENTS_INVALIDATION_MOCK_ACK_HANDLER_H_
+#ifndef COMPONENTS_INVALIDATION_IMPL_MOCK_ACK_HANDLER_H_
+#define COMPONENTS_INVALIDATION_IMPL_MOCK_ACK_HANDLER_H_
 
 #include <map>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
-#include "components/invalidation/ack_handler.h"
-#include "components/invalidation/invalidation_export.h"
-#include "components/invalidation/invalidation_util.h"
+#include "components/invalidation/public/ack_handler.h"
+#include "components/invalidation/public/invalidation_export.h"
+#include "components/invalidation/public/invalidation_util.h"
 
 namespace syncer {
 
@@ -74,4 +74,4 @@ class INVALIDATION_EXPORT MockAckHandler
 
 }  // namespace syncer
 
-#endif  // COMPONENTS_INVALIDATION_MOCK_ACK_HANDLER_H_
+#endif  // COMPONENTS_INVALIDATION_IMPL_MOCK_ACK_HANDLER_H_