Use Ash's ShelfWindowWatcher for app panel windows.

ash/common/shelf/shelf_window_watcher_unittest.cc

Index: ash/common/shelf/shelf_window_watcher_unittest.cc
diff --git a/ash/common/shelf/shelf_window_watcher_unittest.cc b/ash/common/shelf/shelf_window_watcher_unittest.cc
index acf5dc2d04dc86c50e89ca904ecbb14561465dfc..cf59b4fc1289a2880252f0f634609836d630c0ab 100644
--- a/ash/common/shelf/shelf_window_watcher_unittest.cc
+++ b/ash/common/shelf/shelf_window_watcher_unittest.cc
@@ -268,4 +268,28 @@ TEST_F(ShelfWindowWatcherTest, DragWindow) {
   EXPECT_EQ(id, model_->items()[index].id);
 }
 
+// Ensure shelf items are added and removed as panels are opened and closed.
+TEST_F(ShelfWindowWatcherTest, PanelWindow) {
+  // ShelfModel only has an APP_LIST item.
+  EXPECT_EQ(1, model_->item_count());
+
+  // Adding windows with valid ShelfItemType properties adds shelf items.
+  std::unique_ptr<views::Widget> widget1 =
+      CreateTestWidget(nullptr, kShellWindowId_PanelContainer, gfx::Rect());
+  WmWindow* window_1 = WmLookup::Get()->GetWindowForWidget(widget1.get());

[James Cook, 2016/11/02 17:53:44]

super nit: maybe window1 here or widget_1 above?

[msw, 2016/11/10 21:07:46]

Done.

+  window_1->SetIntProperty(WmWindowProperty::SHELF_ITEM_TYPE, TYPE_APP_PANEL);
+  EXPECT_EQ(2, model_->item_count());
+  std::unique_ptr<views::Widget> widget2 =
+      CreateTestWidget(nullptr, kShellWindowId_DefaultContainer, gfx::Rect());
+  WmWindow* window_2 = WmLookup::Get()->GetWindowForWidget(widget2.get());
+  window_2->SetIntProperty(WmWindowProperty::SHELF_ITEM_TYPE, TYPE_APP_PANEL);
+  EXPECT_EQ(3, model_->item_count());
+
+  // Each ShelfItem is removed when the associated window is destroyed.
+  widget1.reset();
+  EXPECT_EQ(2, model_->item_count());
+  widget2.reset();
+  EXPECT_EQ(1, model_->item_count());
+}

[James Cook, 2016/11/02 17:53:44]

Thanks for writing a test.

Is it possible to write a similar (additional?) test that uses a more typical
panel creation code path, rather than tweaking the properties directly? Or do we
have coverage for that elsewhere?

[msw, 2016/11/10 21:07:46]

I added LauncherPlatformAppBrowserTest.AppPanel, restored and updated
ChromeLauncherControllerImplTest.AppPanels, and added some testing here with
ash_shell_lib's PanelWindow. There's also
LauncherPlatformAppBrowserTest.AppPanelClickBehavior.

+
 }  // namespace ash