Fix shelf auto-hide calculation for app-list visibility.

ui/app_list/presenter/app_list_presenter_impl.h

Index: ui/app_list/presenter/app_list_presenter_impl.h
diff --git a/ui/app_list/presenter/app_list_presenter_impl.h b/ui/app_list/presenter/app_list_presenter_impl.h
index 537d1c0dae2668273c2090429db467103f3cd5a4..07d0e88378e1bae9b08bccd83df38fdb22c03058 100644
--- a/ui/app_list/presenter/app_list_presenter_impl.h
+++ b/ui/app_list/presenter/app_list_presenter_impl.h
@@ -54,8 +54,10 @@ class APP_LIST_PRESENTER_EXPORT AppListPresenterImpl
   void Show(int64_t display_id) override;
   void Dismiss() final;
   void ToggleAppList(int64_t display_id) override;
-  bool IsVisible() const override;
-  bool GetTargetVisibility() const override;
+  bool IsVisible(
+      int64_t display_id = display::kInvalidDisplayId) const override;
+  bool GetTargetVisibility(
+      int64_t display_id = display::kInvalidDisplayId) const override;
 
  private:
   friend class test::AppListPresenterImplTestApi;
@@ -96,8 +98,9 @@ class APP_LIST_PRESENTER_EXPORT AppListPresenterImpl
   // Responsible for laying out the app list UI.
   std::unique_ptr<AppListPresenterDelegate> presenter_delegate_;
 
-  // Whether we should show or hide app list widget.
-  bool is_visible_ = false;
+  // The id of the display on which the app list should be shown. A valid id
+  // means the target visiblity is shown, while invalid means hidden.

[James Cook, 2016/11/30 23:27:20]

nit: visibility

+  int64_t target_display_id_ = display::kInvalidDisplayId;

[James Cook, 2016/11/30 23:27:19]

optional: I'd also be OK with separate target_visibility_ and target_display_id_
params if you didn't want to have to explain that invalid means hidden.

 
   // The AppListView this class manages, owned by its widget.
   AppListView* view_ = nullptr;