Handle app custom icon via aura::Window property.

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

Index: chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.cc
diff --git a/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.cc b/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.cc
index 41d5953e1cda765dc682a8263440d1ea3a7683d6..89489f620dedb97f7ec9d4acae03fac4a5dbd1cb 100644
--- a/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.cc
+++ b/chrome/browser/ui/ash/launcher/app_window_launcher_item_controller.cc
@@ -17,8 +17,11 @@
 #include "ui/wm/core/window_animations.h"
 
 AppWindowLauncherItemController::AppWindowLauncherItemController(
-    const ash::ShelfID& shelf_id)
-    : ash::ShelfItemDelegate(shelf_id), observed_windows_(this) {}
+    const ash::ShelfID& shelf_id,
+    ChromeLauncherController* owner)
+    : ash::ShelfItemDelegate(shelf_id),
+      owner_(owner),
+      observed_windows_(this) {}
 
 AppWindowLauncherItemController::~AppWindowLauncherItemController() {}
 
@@ -143,6 +146,8 @@ void AppWindowLauncherItemController::OnWindowPropertyChanged(
       status = ash::STATUS_RUNNING;
     }
     ChromeLauncherController::instance()->SetItemStatus(shelf_id(), status);
+  } else if (key == aura::client::kAppIconKey) {
+    UpdateLauncherItem();
   }
 }
 
@@ -174,3 +179,19 @@ AppWindowLauncherItemController::ActivateOrAdvanceToNextAppWindow(
   }
   return ash::SHELF_ACTION_NONE;
 }
+
+void AppWindowLauncherItemController::UpdateLauncherItem() {
+  const gfx::ImageSkia* app_icon = nullptr;
+  ui::BaseWindow* last_active_window = GetLastActiveWindow();
+  if (last_active_window && last_active_window->GetNativeWindow()) {
+    app_icon = last_active_window->GetNativeWindow()->GetProperty(
+        aura::client::kAppIconKey);
+  }
+  if (app_icon && !app_icon->isNull()) {
+    set_image_set_by_controller(true);
+    owner()->SetLauncherItemImage(shelf_id(), *app_icon);
+  } else if (image_set_by_controller()) {
+    set_image_set_by_controller(false);
+    owner()->UpdateAppItemImage(shelf_id().app_id);
+  }
+}