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
new file mode 100644
index 0000000000000000000000000000000000000000..eb338872f9a6aeac4247f45ea2b83ac471fbe4a5
--- /dev/null
+++ b/components/physical_web/data_source/physical_web_listener.h
@@ -0,0 +1,26 @@
+// 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_
+
+#include <string>
+
+// Class for being notified when Physical Web data changes.
+class PhysicalWebListener {
+ public:
+
+  // OnFound(url) will be called when a new URL has been found.
+  virtual void OnFound(const std::string& url) = 0;
+
+  // OnLost(url) will be called when a URL can no longer be seen.
+  virtual void OnLost(const std::string& url) = 0;
+
+  // OnDistanceChagned(url, distance_estimate) will be called when the distance
+  // estimate is changed for the URL.
+  virtual void OnDistanceChanged(const std::string& url,
+                                 double distance_estimate) = 0;
+};
+
+#endif // COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_LISTENER_H_