Draggable peeking/fullscreen launcher with transparent background.

ash/shelf/shelf_layout_manager.h

 // Copyright 2012 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_SHELF_SHELF_LAYOUT_MANAGER_H_
 #define ASH_SHELF_SHELF_LAYOUT_MANAGER_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
@@ skipping 42 matching lines @@
     : public ShellObserver,
       public aura::client::ActivationChangeObserver,
       public keyboard::KeyboardControllerObserver,
       public LockStateObserver,
       public wm::WmSnapToPixelLayoutManager,
       public SessionObserver {
  public:
   ShelfLayoutManager(ShelfWidget* shelf_widget, WmShelf* wm_shelf);
   ~ShelfLayoutManager() override;
 
+  // Called from wm_shelf to prevent the translucent background from the shelf
+  // from overlapping with the translucent background from the launcher.
+  void AppListIsActive(bool active);

[vadimt, 2017/05/22 23:36:56]

Also: rename to OnAppListIsActive.
You don't have to write things like "to prevent XXX" since the purpose can
change in future.

[newcomer, 2017/05/25 23:10:51]

Done.

+
   bool updating_bounds() const { return updating_bounds_; }
 
   // Clears internal data for shutdown process.
   void PrepareForShutdown();
-
   // Returns whether the shelf and its contents (shelf, status) are visible
   // on the screen.
   bool IsVisible() const;
 
   // Returns the ideal bounds of the shelf assuming it is visible.
   gfx::Rect GetIdealBounds();
 
   // Returns the preferred size of the shelf for the target visibility state.
   gfx::Size GetPreferredSize();
 
@@ skipping 228 matching lines @@
 
   // Current state.
   State state_;
 
   ShelfWidget* shelf_widget_;
   WmShelf* wm_shelf_;
 
   // Do any windows overlap the shelf? This is maintained by WorkspaceManager.
   bool window_overlaps_shelf_;
 
+  bool app_list_is_active_ = false;

[vadimt, 2017/05/22 23:36:56]

Is there a reasonable way to find out from here whether launcher is active
without introducing a variable?

[xiyuan, 2017/05/24 18:28:17]

Think we can use Shell::Get()->app_list()->IsVisible() (or
GetTargetVisibility()).

[newcomer, 2017/05/25 23:10:50]

Acknowledged.

[newcomer, 2017/05/25 23:10:51]

AppListIsActive (now OnAppListIsActive) actually forces the shelf to hide it's
transparent background. 

I think it is more efficient to make a call from the presenter delegate every
time the applist is created(and set app_list_is_active_) instead of polling for
the applist every time GetShelfBackgroundType is called.

I'd be happy to hear arguments against this!

   base::OneShotTimer auto_hide_timer_;
 
   // Whether the mouse was over the shelf when the auto hide timer started.
   // False when neither the auto hide timer nor the timer task are running.
   bool mouse_over_shelf_when_auto_hide_timer_started_;
 
   base::ObserverList<ShelfLayoutManagerObserver> observers_;
 
   // The shelf reacts to gesture-drags, and can be set to auto-hide for certain
   // gestures. Some shelf behaviour (e.g. visibility state, background color
@@ skipping 39 matching lines @@
                  keyboard::KeyboardControllerObserver>
       keyboard_observer_;
   ScopedSessionObserver scoped_session_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfLayoutManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_LAYOUT_MANAGER_H_