[Downloads] Ask DownloadHistory if a download was from history.

chrome/browser/download/download_history.h

Index: chrome/browser/download/download_history.h
diff --git a/chrome/browser/download/download_history.h b/chrome/browser/download/download_history.h
index e983c90964ff7cd3ab05215d9787b43e041e9c3f..ea51ab4c43af2c7b9e3f1589d5e91aad3cbb8106 100644
--- a/chrome/browser/download/download_history.h
+++ b/chrome/browser/download/download_history.h
@@ -67,8 +67,11 @@ class DownloadHistory : public AllDownloadItemNotifier::Observer {
     virtual void OnDownloadHistoryDestroyed() {}
   };
 
-  // Returns true if the item is persisted.
-  static bool IsPersisted(content::DownloadItem* item);
+  // Returns true if the download is persisted. Not reliable when called from
+  // within a DownloadManager::Observer::OnDownloadCreated handler since the
+  // persisted state may not yet have been updated for a download that was
+  // restored from history.
+  static bool IsPersisted(const content::DownloadItem* item);
 
   // Neither |manager| nor |history| may be NULL.
   // DownloadService creates DownloadHistory some time after DownloadManager is
@@ -82,6 +85,14 @@ class DownloadHistory : public AllDownloadItemNotifier::Observer {
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
+  // Returns true if the download was restored from history. Safe to call from
+  // within a DownloadManager::Observer::OnDownloadCreated handler and can be
+  // used to distinguish between downloads that were created due to new requests
+  // vs. downloads that were created due to being restored from history. Note
+  // that the return value is only reliable for downloads that were restored by
+  // this specific DownloadHistory instance.
+  bool WasRestoredFromHistory(const content::DownloadItem* item) const;
+
  private:
   typedef std::set<content::DownloadItem*> ItemSet;