Cleanup usage of history namespace in components/history

components/history/core/browser/page_usage_data.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.
 
 #ifndef COMPONENTS_HISTORY_CORE_BROWSER_PAGE_USAGE_DATA_H__
 #define COMPONENTS_HISTORY_CORE_BROWSER_PAGE_USAGE_DATA_H__
 
 #include "base/strings/string16.h"
 #include "components/history/core/browser/history_types.h"
 #include "url/gurl.h"
 
 class SkBitmap;
 
+namespace history {
+
 /////////////////////////////////////////////////////////////////////////////
 //
 // PageUsageData
 //
 // A per domain usage data structure to compute and manage most visited
 // pages.
 //
-// See History::QueryPageUsageSince()
+// See QueryPageUsageSince()
 //
 /////////////////////////////////////////////////////////////////////////////
 class PageUsageData {
  public:
-  explicit PageUsageData(history::SegmentID id);
+  explicit PageUsageData(SegmentID id);
 
   virtual ~PageUsageData();
 
   // Return the url ID
-  history::SegmentID GetID() const {
-    return id_;
-  }
+  SegmentID GetID() const { return id_; }
 
   void SetURL(const GURL& url) {
     url_ = url;
   }
 
   const GURL& GetURL() const {
     return url_;
   }
 
   void SetTitle(const base::string16& s) {
     title_ = s;
   }
 
   const base::string16& GetTitle() const {
     return title_;
   }
 
   void SetScore(double v) {
     score_ = v;
   }
 
   double GetScore() const {
     return score_;
   }
 
   // Sort predicate to sort instances by score (high to low)
   static bool Predicate(const PageUsageData* dud1, const PageUsageData* dud2);
 
  private:
-  history::SegmentID id_;
+  SegmentID id_;
   GURL url_;
   base::string16 title_;
 
   double score_;
 };
 
+}  // namespace history
+
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_PAGE_USAGE_DATA_H__