downloads: break downloads.js into more classes/files.

chrome/browser/download/download_item_model.h

Index: chrome/browser/download/download_item_model.h
diff --git a/chrome/browser/download/download_item_model.h b/chrome/browser/download/download_item_model.h
index 68444ec7b4ec85fc4a61f85a7f04a9f7ef73dbb1..ee6fb0c332d7e6692096f4ad4f4f126534edcab5 100644
--- a/chrome/browser/download/download_item_model.h
+++ b/chrome/browser/download/download_item_model.h
@@ -152,6 +152,12 @@ class DownloadItemModel {
   // ShouldPreferOpeningInBrowser().
   void OpenUsingPlatformHandler();
 
+  // Whether the download was removed and this is currently being undone.
+  bool IsBeingRevived() const;
+
+  // Set whether the download is being revived.
+  void SetIsBeingRevived(bool is_being_revived);
+
   content::DownloadItem* download() { return download_; }
 
  private: