Backout Bug 399838 to investigate Ts regression.

browser/components/sessionstore/src/nsSessionStore.js

@@ -420,8 +420,10 @@ SessionStoreService.prototype = {
         delete this._initialState;
       }
       
-      // restart any interrupted downloads
-      aWindow.setTimeout(this.retryDownloads, 0);
+      if (this._lastSessionCrashed) {
+        // restart any interrupted downloads
+        aWindow.setTimeout(this.retryDownloads, 0);
+      }
     }
     
     var tabbrowser = aWindow.getBrowser();