Downloads: Added transient flag to download item and download database

content/browser/download/download_item_impl.h

Index: content/browser/download/download_item_impl.h
diff --git a/content/browser/download/download_item_impl.h b/content/browser/download/download_item_impl.h
index 7b953b24387786dc3ddea74fa517f38e6d97c0a6..75bf52bfc5f2e8df4b796bda0fe5258fec71a246 100644
--- a/content/browser/download/download_item_impl.h
+++ b/content/browser/download/download_item_impl.h
@@ -76,6 +76,7 @@ class CONTENT_EXPORT DownloadItemImpl
       DownloadInterruptReason interrupt_reason,
       bool opened,
       const base::Time& last_access_time,
+      bool visible,
       const std::vector<DownloadItem::ReceivedSlice>& received_slices,
       const net::NetLogWithSource& net_log);
 
@@ -164,6 +165,7 @@ class CONTENT_EXPORT DownloadItemImpl
   bool GetAutoOpened() override;
   bool GetOpened() const override;
   base::Time GetLastAccessTime() const override;
+  bool IsVisible() const override;
   BrowserContext* GetBrowserContext() const override;
   WebContents* GetWebContents() const override;
   void OnContentCheckCompleted(DownloadDangerType danger_type) override;
@@ -627,6 +629,9 @@ class CONTENT_EXPORT DownloadItemImpl
   // Time when the download was last accessed.
   base::Time last_access_time_;
 
+  // Whether the download item should be visible.
+  bool visible_ = true;
+
   // Did the delegate delay calling Complete on this download?
   bool delegate_delayed_complete_ = false;