For downloads requiring a user gesture, also require...

chrome/browser/download/download_history.h

 // Copyright (c) 2011 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 CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_
 #pragma once
 
+#include <map>
+
 #include "base/basictypes.h"
 #include "chrome/browser/history/history.h"
 #include "content/browser/cancelable_request.h"
 
 class DownloadItem;
 class Profile;
 
 namespace base {
 class Time;
 }
 
 // Interacts with the HistoryService on behalf of the download subsystem.
 class DownloadHistory {
  public:
+  typedef Callback2<int32, bool>::Type VisitedBeforeDoneCallback;
+
   // A fake download table ID which represents a download that has started,
   // but is not yet in the table.
   static const int kUninitializedHandle;
 
   explicit DownloadHistory(Profile* profile);
   ~DownloadHistory();
 
   // Retrieves DownloadCreateInfos saved in the history.
   void Load(HistoryService::DownloadQueryCallback* callback);
 
+  // Checks whether |referrer_url| has been visited before today.
+  void CheckVisitedReferrerBefore(int32 download_id,
+                                  const GURL& referrer_url,
+                                  VisitedBeforeDoneCallback* callback);
+
   // Adds a new entry for a download to the history database.
   void AddEntry(DownloadItem* download_item,
                 HistoryService::DownloadCreateCallback* callback);
 
   // Updates the history entry for |download_item|.
   void UpdateEntry(DownloadItem* download_item);
 
   // Updates the download path for |download_item| to |new_path|.
   void UpdateDownloadPath(DownloadItem* download_item,
                           const FilePath& new_path);
 
   // Removes |download_item| from the history database.
   void RemoveEntry(DownloadItem* download_item);
 
   // Removes download-related history entries in the given time range.
   void RemoveEntriesBetween(const base::Time remove_begin,
                             const base::Time remove_end);
 
   // Returns a new unique database handle which will not collide with real ones.
   int64 GetNextFakeDbHandle();
 
  private:
+  typedef std::map<HistoryService::Handle,
+                   std::pair<int32, VisitedBeforeDoneCallback*> >
+      VisitedBeforeRequestsMap;
+
+  void OnGotVisitCountToHost(HistoryService::Handle handle,
+                             bool found_visits,
+                             int count,
+                             base::Time first_visit);
+
   Profile* profile_;
 
   // In case we don't have a valid db_handle, we use |fake_db_handle_| instead.
   // This is useful for incognito mode or when the history database is offline.
   // Downloads are expected to have unique handles, so we decrement the next
   // fake handle value on every use.
   int64 next_fake_db_handle_;
 
   CancelableRequestConsumer history_consumer_;
 
+  // The outstanding requests made by CheckVisitedReferrerBefore().
+  VisitedBeforeRequestsMap visited_before_requests_;
+
   DISALLOW_COPY_AND_ASSIGN(DownloadHistory);
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_