Notify SelectFileDialog when MediaRouterFileDialog is destroyed

This prevents SelectFileDialog::Listener methods implemented by
MediaRouterFileDialog from getting called after it is destroyed.

Bug: 907273
Change-Id: I5ec03d832f1062ff1c2259f765f397b7af4c90a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898404Reviewed-by: Brandon Tolsch <btolsch@chromium.org>
Commit-Queue: Takumi Fujimoto <takumif@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712732}

chrome/browser/ui/media_router/media_router_file_dialog.cc

@@ -69,9 +69,12 @@ ui::SelectFileDialog::FileTypeInfo GetAudioVideoFileTypeInfo() {
 
 }  // namespace
 
-// FileSystemDelegate default implementations
 MediaRouterFileDialog::FileSystemDelegate::FileSystemDelegate() = default;
-MediaRouterFileDialog::FileSystemDelegate::~FileSystemDelegate() = default;
+
+MediaRouterFileDialog::FileSystemDelegate::~FileSystemDelegate() {
+  if (select_file_dialog_)
+    select_file_dialog_->ListenerDestroyed();
+}
 
 bool MediaRouterFileDialog::FileSystemDelegate::FileExists(
     const base::FilePath& file_path) const {