Handle app custom icon via aura::Window property.

chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_controller.cc

Index: chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_controller.cc
diff --git a/chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_controller.cc b/chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_controller.cc
index acda1fb5690d3d48047cb8abc0cabd95baa5c561..ff798230f9eb918586b0cde631df51c27b63d7fe 100644
--- a/chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_controller.cc
+++ b/chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_controller.cc
@@ -24,8 +24,9 @@
 #include "ui/wm/core/window_animations.h"
 
 ExtensionAppWindowLauncherItemController::
-    ExtensionAppWindowLauncherItemController(const ash::ShelfID& shelf_id)
-    : AppWindowLauncherItemController(shelf_id) {}
+    ExtensionAppWindowLauncherItemController(const ash::ShelfID& shelf_id,
+                                             ChromeLauncherController* owner)
+    : AppWindowLauncherItemController(shelf_id, owner) {}
 
 ExtensionAppWindowLauncherItemController::
     ~ExtensionAppWindowLauncherItemController() {}
@@ -59,8 +60,15 @@ ash::MenuItemList ExtensionAppWindowLauncherItemController::GetAppMenuItems(
         favicon::ContentFaviconDriver::FromWebContents(
             app_window->web_contents());
     gfx::Image icon = favicon_driver->GetFavicon();
-    if (icon.IsEmpty())
-      icon = app_window->app_icon();
+    if (icon.IsEmpty()) {
+      const gfx::ImageSkia* app_icon = nullptr;
+      if (app_window->GetNativeWindow()) {
+        app_icon = app_window->GetNativeWindow()->GetProperty(
+            aura::client::kAppIconKey);
+      }
+      if (app_icon && !app_icon->isNull())
+        icon = gfx::Image(*app_icon);

[stevenjb, 2017/05/23 17:00:19]

Maybe put the above in AppWindow as GetAppIcon() instead?

[khmel, 2017/05/23 17:35:00]

I am not very sure. Actually ChromeNativeAppWindowViews is WidgetDelegate, and
as a delegate it implements:
  gfx::ImageSkia GetWindowAppIcon() override;
  gfx::ImageSkia GetWindowIcon() override;

I don't feel that asking app window back is good idea. Let decide how app icon
looks in one place, here. WDYT?

[msw, 2017/05/23 18:13:12]

Hmm, it seems like this code should call
ChromeNativeAppWindowViews::GetWindowIcon, and fallback to
ChromeNativeAppWindowViews::GetWindowAppIcon if the former is null/empty. Can we
call those here, perhaps indirectly if needed (eg. via AppWindow)?

+    }
     if (!icon.IsEmpty())
       item->image = *icon.ToSkBitmap();
     items.push_back(std::move(item));