Introduce a layering in the invalidation component as public and impl

components/invalidation/impl/invalidator.h

 // 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.
 //
 // Interface to the invalidator, which is an object that receives
 // invalidations for registered object IDs. The corresponding
 // InvalidationHandler is notifier when such an event occurs.
 
-#ifndef COMPONENTS_INVALIDATION_INVALIDATOR_H_
-#define COMPONENTS_INVALIDATION_INVALIDATOR_H_
+#ifndef COMPONENTS_INVALIDATION_IMPL_INVALIDATOR_H_
+#define COMPONENTS_INVALIDATION_IMPL_INVALIDATOR_H_
 
 #include <string>
 
 #include "base/callback.h"
-#include "components/invalidation/invalidation_export.h"
-#include "components/invalidation/invalidation_util.h"
-#include "components/invalidation/invalidator_state.h"
+#include "components/invalidation/public/invalidation_export.h"
+#include "components/invalidation/public/invalidation_util.h"
+#include "components/invalidation/public/invalidator_state.h"
 
 namespace syncer {
 class InvalidationHandler;
 
 class INVALIDATION_EXPORT Invalidator {
  public:
   Invalidator();
   virtual ~Invalidator();
 
   // Clients should follow the pattern below:
@@ skipping 51 matching lines @@
   // once.
   virtual void UpdateCredentials(
       const std::string& email, const std::string& token) = 0;
 
   // Requests internal detailed status to be posted back to the callback.
   virtual void RequestDetailedStatus(
       base::Callback<void(const base::DictionaryValue&)> callback) const = 0;
 };
 }  // namespace syncer
 
-#endif  // COMPONENTS_INVALIDATION_INVALIDATOR_H_
+#endif  // COMPONENTS_INVALIDATION_IMPL_INVALIDATOR_H_