Avoid runtime error when window.reload is not available.

appWindow object doesn't have reload() method ready until the window is
loaded. This is a quick fix to avoid crashing the background script by
user operation.

Test: manually verified as noted in the bug
Bug: 789226
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Ie2266792d8ca62bd0bae74ff2824b72221acbdb7
Reviewed-on: https://chromium-review.googlesource.com/800910Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Tatsuhisa Yamaguchi <yamaguchi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#522000}

ui/file_manager/file_manager/background/js/app_window_wrapper.js

@@ -296,7 +296,15 @@ SingletonAppWindowWrapper.prototype.launch =
   this.queue.run(function(nextStep) {
     this.window_.contentWindow.appState = appState;
     this.window_.contentWindow.appReopen = reopen;
+    if (!this.window_.contentWindow.reload) {
+      // Currently the queue is not made to wait for window loading after
+      // creating window. Therefore contentWindow might not have the reload()
+      // function ready yet. This happens when launching the same app twice
+      // quickly. See crbug.com/789226.
+      console.error('Window reload requested before loaded. Skiping.');
+    } else {
       this.window_.contentWindow.reload();
+    }
     if (opt_callback)
       opt_callback();
     nextStep();