Make DownloadHistory observe manager, items

chrome/browser/history/history_backend.h

Index: chrome/browser/history/history_backend.h
diff --git a/chrome/browser/history/history_backend.h b/chrome/browser/history/history_backend.h
index 4346d82fe65b85f7b3ec0ff61596fb532723e2e5..1c1d2dbd332e1f155fe47fad84cb4af97960268e 100644
--- a/chrome/browser/history/history_backend.h
+++ b/chrome/browser/history/history_backend.h
@@ -27,11 +27,8 @@
 
 class BookmarkService;
 class TestingProfile;
-struct ThumbnailScore;
-
-namespace content {
 struct DownloadPersistentStoreInfo;
-}
+struct ThumbnailScore;
 
 namespace history {
 #if defined(OS_ANDROID)
@@ -292,17 +289,15 @@ class HistoryBackend : public base::RefCountedThreadSafe<HistoryBackend>,
   // Downloads -----------------------------------------------------------------
 
   void GetNextDownloadId(scoped_refptr<DownloadNextIdRequest> request);
-  void QueryDownloads(scoped_refptr<DownloadQueryRequest> request);
+  void QueryDownloads(const HistoryService::DownloadQueryCallback& callback);
   void CleanUpInProgressEntries();
-  void UpdateDownload(const content::DownloadPersistentStoreInfo& data);
-  void UpdateDownloadPath(const FilePath& path, int64 db_handle);
-  void CreateDownload(scoped_refptr<DownloadCreateRequest> request,
-                      int32 id,
-                      const content::DownloadPersistentStoreInfo& info);
-  void RemoveDownload(int64 db_handle);
-  void RemoveDownloadsBetween(const base::Time remove_begin,
-                              const base::Time remove_end);
-  void RemoveDownloads(const base::Time remove_end);
+  void UpdateDownload(const DownloadPersistentStoreInfo& data);
+  void CreateDownload(const DownloadPersistentStoreInfo& info,
+                      const HistoryService::DownloadCreateCallback& callback);
+  void GetVisibleVisitCountToHostSimple(
+      const GURL& url,
+      const HistoryService::GetVisibleVisitCountToHostSimpleCallback& callback);
+  void RemoveDownloads(const std::set<int64>& handles);
 
   // Segment usage -------------------------------------------------------------