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

ash/common/shelf/app_list_button.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_COMMON_SHELF_APP_LIST_BUTTON_H_
 #define ASH_COMMON_SHELF_APP_LIST_BUTTON_H_
 
 #include "ash/ash_export.h"
 #include "base/macros.h"
 #include "ui/views/controls/button/image_button.h"
 
 namespace ash {
 class InkDropButtonListener;
 class ShelfView;
 class WmShelf;
 
 // Button used for the AppList icon on the shelf.
 class ASH_EXPORT AppListButton : public views::ImageButton {
  public:
   AppListButton(InkDropButtonListener* listener,
                 ShelfView* shelf_view,
                 WmShelf* wm_shelf);
   ~AppListButton() override;
 
   void OnAppListShown();
   void OnAppListDismissed();
 
-  bool draw_background_as_active() { return draw_background_as_active_; }
+  bool is_showing_app_list() const { return is_showing_app_list_; }
+
+  bool draw_background_as_active() const { return draw_background_as_active_; }
 
   // Sets alpha value of the background and schedules a paint.
   void SetBackgroundAlpha(int alpha);
 
  protected:
   // views::ImageButton overrides:
   bool OnMousePressed(const ui::MouseEvent& event) override;
   void OnMouseReleased(const ui::MouseEvent& event) override;
   void OnMouseCaptureLost() override;
   bool OnMouseDragged(const ui::MouseEvent& event) override;
@@ skipping 17 matching lines @@
   void PaintMd(gfx::Canvas* canvas);
 
   // Helper function to paint the AppList button in Chrome OS non-MD.
   void PaintAppListButton(gfx::Canvas* canvas,
                           const gfx::ImageSkia& foreground_image);
 
   // Get the center point of the app list button used to draw its background and
   // ink drops.
   gfx::Point GetCenterPoint() const;
 
+  // True if the app list is currently showing for this button.

[James Cook, 2016/12/01 02:02:07]

nit: button/display (since the fact that this is per-display is important). You
might also comment that this is different from WmShell::IsApplistVisible().

Basically, it's weird that we can't use WmShell::IsApplistVisible() so it would
be nice to say something about that somewhere.

[msw, 2016/12/01 04:18:13]

Done.

+  bool is_showing_app_list_ = false;

[James Cook, 2016/12/01 02:02:07]

nit: I prefer to either initialize all members in the header or all members in
the .cc file. In this case, it looks like they will all need to go in .cc since
some of them are constructed.

[msw, 2016/12/01 04:18:13]

Done.

+
   // True if the background should render as active, regardless of the state of
   // the application list.
-  bool draw_background_as_active_;
+  bool draw_background_as_active_ = false;
 
   // Alpha value used to paint the background.
-  int background_alpha_;
+  int background_alpha_ = 0;
 
   InkDropButtonListener* listener_;
   ShelfView* shelf_view_;
   WmShelf* wm_shelf_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListButton);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_APP_LIST_BUTTON_H_