Make DownloadHistory observe manager, items

Rip out half of DownloadManagerDelegate.
Make DownloadManager create persisted DownloadItems one at a time and return them to DownloadHistory.
Move DownloadPersistentStoreInfo from content to chrome.
Kill DownloadDatabase::CheckThread(). (Leftover from 85408.)
Change DownloadDatabase::RemoveDownloads() to take an explicit set of db_handles.
Merge DownloadDatabase::UpdateDownload[Path]().

After this CL, I'll send out another one to remove the usage of CancelableRequest from the downloads-specific HistoryService APIs.

BUG=154309

Review URL: https://chromiumcodereview.appspot.com/10915180

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168670 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/content/browser/download/download_item_impl_delegate.h b/content/browser/download/download_item_impl_delegate.h
index 323aa6b..4d6beb7 100644
--- a/content/browser/download/download_item_impl_delegate.h
+++ b/content/browser/download/download_item_impl_delegate.h
@@ -78,9 +78,9 @@
   virtual void DownloadCompleted(DownloadItemImpl* download);
   virtual void DownloadOpened(DownloadItemImpl* download);
   virtual void DownloadRemoved(DownloadItemImpl* download);
-  virtual void DownloadRenamedToIntermediateName(
-      DownloadItemImpl* download);
-  virtual void DownloadRenamedToFinalName(DownloadItemImpl* download);
+
+  // Show the download in the browser.
+  virtual void ShowDownloadInBrowser(DownloadItemImpl* download);
 
   // Assert consistent state for delgate object at various transitions.
   virtual void AssertStateConsistent(DownloadItemImpl* download) const;