CrOS Shelf: Add a test that performs a drag+drop+screenshot

The test starts dragging an app out of the main shelf, drags it into
the overflow shelf, and while the drag is still in progress, takes a
screenshot.

This is part of trying to reproduce the linked bug and add test
coverage. This test passes, so I'll need to look into what other
conditions are required, or maybe this bug doesn't happen any longer.
Regardless, it doesn't hurt to have this test.

Bug: 997612
Change-Id: I5bbaca6add0c13fa9df6fa04ede43d1b8519c10e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1785679Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Manu Cornet <manucornet@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693909}

ash/shelf/shelf_view_unittest.cc

@@ -44,6 +44,8 @@
 #include "ash/system/status_area_widget.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/ash_test_helper.h"
+#include "ash/test/ui_controls_factory_ash.h"
+#include "ash/test_screenshot_delegate.h"
 #include "ash/test_shell_delegate.h"
 #include "ash/wallpaper/wallpaper_controller_impl.h"
 #include "ash/wallpaper/wallpaper_controller_test_api.h"
@@ -68,6 +70,7 @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/l10n/l10n_util.h"
+#include "ui/base/test/ui_controls.h"
 #include "ui/base/ui_base_features.h"
 #include "ui/compositor/layer.h"
 #include "ui/display/display.h"
@@ -1823,6 +1826,71 @@ TEST_F(ShelfViewTest, CheckDragAndDropFromShelfToOtherShelf) {
                                           true /* cancel */);
 }
 
+// Checks taking a screenshot while dragging an app into the overflow menu.
+TEST_F(ShelfViewTest, TestDragToOverflowAndTakeScreenshot) {
+  // We'll need UI controls to trigger the accelerator for taking a screenshot.
+  ui_controls::InstallUIControlsAura(test::CreateAshUIControls());
+
+  AddAppShortcutsUntilOverflow();
+  // Add a couple more to make sure we can easily drag into the overflow menu.
+  AddAppShortcut();
+  AddAppShortcut();
+  test_api_->ShowOverflowBubble();
+  ASSERT_TRUE(shelf_view_->IsShowingOverflowBubble());
+
+  ShelfView* overflow_shelf_view = shelf_view_->overflow_shelf();
+  ShelfViewTestAPI test_api_for_overflow(overflow_shelf_view);
+  EXPECT_LE(2, overflow_shelf_view->number_of_visible_apps());
+
+  views::View* drag_button =
+      test_api_.get()->GetViewAt(shelf_view_->last_visible_index());
+  ShelfID drag_id = GetItemId(shelf_view_->last_visible_index());
+  const gfx::Point drag_point = drag_button->GetBoundsInScreen().CenterPoint();
+
+  ui::test::EventGenerator* generator = GetEventGenerator();
+  generator->set_current_screen_location(drag_point);
+
+  // Rip the item off the main shelf.
+  generator->PressLeftButton();
+  const gfx::Point rip_off_point(drag_point.x(), 0);
+  generator->MoveMouseTo(rip_off_point);
+  test_api_.get()->RunMessageLoopUntilAnimationsDone();
+  test_api_for_overflow.RunMessageLoopUntilAnimationsDone();
+  ASSERT_TRUE(test_api_.get()->IsRippedOffFromShelf());
+  ASSERT_FALSE(test_api_.get()->DraggedItemToAnotherShelf());
+
+  // Move the dragged item into the overflow shelf.
+  views::View* drop_button = test_api_for_overflow.GetViewAt(
+      overflow_shelf_view->last_visible_index());
+  const gfx::Point drop_point = drop_button->GetBoundsInScreen().CenterPoint();
+
+  generator->MoveMouseTo(drop_point);
+  test_api_.get()->RunMessageLoopUntilAnimationsDone();
+  test_api_for_overflow.RunMessageLoopUntilAnimationsDone();
+  ASSERT_TRUE(test_api_.get()->IsRippedOffFromShelf());
+  ASSERT_TRUE(test_api_.get()->DraggedItemToAnotherShelf());
+
+  // Do not release the mouse button yet.
+
+  TestScreenshotDelegate* screenshot_delegate = GetScreenshotDelegate();
+  screenshot_delegate->set_can_take_screenshot(true);
+  EXPECT_EQ(0, screenshot_delegate->handle_take_screenshot_count());
+
+  // Send the key press to take a screenshot, synchronously.
+  base::RunLoop loop;
+  ui_controls::SendKeyPressNotifyWhenDone(
+      Shell::GetPrimaryRootWindow(), ui::VKEY_SNAPSHOT, false /* ctrl */,
+      false /* shift */, false /* alt */, false /* cmd */, loop.QuitClosure());
+  loop.Run();
+  EXPECT_EQ(1, screenshot_delegate->handle_take_screenshot_count());
+
+  // Now, finally complete the drag and verify that it was successful.
+  generator->ReleaseLeftButton();
+  EXPECT_EQ(drag_id, GetItemId(overflow_shelf_view->last_visible_index()));
+
+  ui_controls::InstallUIControlsAura(nullptr);
+}
+
 // Checks drag-reorder items within the overflow shelf.
 TEST_F(ShelfViewTest, TestDragWithinOverflow) {
   // Prepare the overflow and open it.