Remove old code from CrostiniApps::OnAppIconUpdated

I submitted crrev.com/c/2226106 before I saw the final comment saying
this could be removed. Remove it now.

R=dominickn@chromium.org

Bug: 1088393
Change-Id: I973ae149da73a1c9ddcc024e52f5ac1016dd73b6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2249288
Commit-Queue: Fergus Dall <sidereal@google.com>
Commit-Queue: Dominick Ng <dominickn@chromium.org>
Auto-Submit: Fergus Dall <sidereal@google.com>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779600}

chrome/browser/apps/app_service/crostini_apps.cc

@@ -247,11 +247,6 @@ void CrostiniApps::OnRegistryUpdated(
 void CrostiniApps::OnAppIconUpdated(const std::string& app_id,
                                     ui::ScaleFactor scale_factor,
                                     const std::string& compressed_icon_data) {
-  apps::mojom::AppPtr app = apps::mojom::App::New();
-  app->app_type = apps::mojom::AppType::kCrostini;
-  app->app_id = app_id;
-  app->icon_key = NewIconKey(app_id);
-
   auto range = app_icon_callbacks_.equal_range(app_id);
   for (auto it = range.first; it != range.second; it++) {
     apps::mojom::IconCompression icon_compression;