Dismiss the launcher if the state is CLOSED when ending the drag from shelf.

Drag up the closing launcher on the shelf area and end with FLING_START event
with velocity_y that exceeds |kAppListDragVelocityThreshold| will end with
setting the launcher state to FULLSCREEN_ALL_APPS. But the state was already
set to CLOSED after close animation is started and hence setting state to
FULLSCREEN_ALL_APPS does not have effect. Should dismiss the launcher instead
of setting its state in this case.
Related cl: https://chromium-review.googlesource.com/c/chromium/src/+/667949

Bug: 766324
Change-Id: Ibac26da14cd18c99046b801c96c974484f5d30c6
Reviewed-on: https://chromium-review.googlesource.com/798321
Commit-Queue: min c <minch@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520642}

ui/app_list/presenter/app_list_presenter_impl.cc

@@ -157,10 +157,12 @@ void AppListPresenterImpl::UpdateYPositionAndOpacity(int y_position_in_screen,
 void AppListPresenterImpl::EndDragFromShelf(
     mojom::AppListState app_list_state) {
   if (view_) {
-    if (app_list_state == mojom::AppListState::CLOSED)
+    if (app_list_state == mojom::AppListState::CLOSED ||
+        view_->app_list_state() == AppListViewState::CLOSED) {
       view_->Dismiss();
-    else
+    } else {
       view_->SetState(AppListViewState(app_list_state));
+    }
     view_->SetIsInDrag(false);
     view_->DraggingLayout();
   }