Expose Physical Web data

components/physical_web/data_source/physical_web_listener.h

Index: components/physical_web/data_source/physical_web_listener.h
diff --git a/components/physical_web/data_source/physical_web_listener.h b/components/physical_web/data_source/physical_web_listener.h
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index 0000000000000000000000000000000000000000..8eb312bad8245b36eae6d4e5afbda7f1c5f0d348
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+++ b/components/physical_web/data_source/physical_web_listener.h
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+// 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.
+
+#ifndef COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_LISTENER_H_
+#define COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_LISTENER_H_
+
+// Class for being notified when Physical Web data changes.
+class PhysicalWebListener {
+ public:
+
+  // On update will be called when the physical web data source updates.
+  virtual void OnUpdate() = 0;
+};
+
+#endif // COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_LISTENER_H_