[PhysicalWeb] Add physical_web namespace.

components/physical_web/data_source/physical_web_data_source.h

 // 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_DATA_SOURCE_H_
 #define COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_DATA_SOURCE_H_
 
 #include <memory>
 
 namespace base {
 class ListValue;
 }
 
+namespace physical_web {
+
 class PhysicalWebListener;
 
 // Dictionary keys for reading Physical Web URL metadata.
-extern const char kPhysicalWebDescriptionKey[];
-extern const char kPhysicalWebDistanceEstimateKey[];
-extern const char kPhysicalWebGroupIdKey[];
-extern const char kPhysicalWebIconUrlKey[];
-extern const char kPhysicalWebResolvedUrlKey[];
-extern const char kPhysicalWebScanTimestampKey[];
-extern const char kPhysicalWebScannedUrlKey[];
-extern const char kPhysicalWebTitleKey[];
+extern const char kDescriptionKey[];
+extern const char kDistanceEstimateKey[];
+extern const char kGroupIdKey[];
+extern const char kIconUrlKey[];
+extern const char kResolvedUrlKey[];
+extern const char kScanTimestampKey[];
+extern const char kScannedUrlKey[];
+extern const char kTitleKey[];
 
 // Helper class for accessing Physical Web metadata and controlling the scanner.
 class PhysicalWebDataSource {
  public:
   virtual ~PhysicalWebDataSource() {}
 
   // Starts scanning for Physical Web URLs. If |network_request_enabled| is
   // true, discovered URLs will be sent to a resolution service.
   virtual void StartDiscovery(bool network_request_enabled) = 0;
 
@@ skipping 14 matching lines @@
   virtual bool HasUnresolvedDiscoveries() = 0;
 
   // Register for changes to Physical Web URLs and associated page metadata.
   virtual void RegisterListener(PhysicalWebListener* physical_web_listener) = 0;
 
   // Unregister for changes to Physical Web URLs and associated page metadata.
   virtual void UnregisterListener(
       PhysicalWebListener* physical_web_listener) = 0;
 };
 
+}  // namespace physical_web
+
 #endif  // COMPONENTS_PHYSICAL_WEB_DATA_SOURCE_PHYSICAL_WEB_DATA_SOURCE_H_