Implement "pinned" mode in ash.

ash/aura/wm_shell_aura.h

 // Copyright 2016 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_AURA_WM_SHELL_AURA_H_
 #define ASH_AURA_WM_SHELL_AURA_H_
 
 #include "ash/ash_export.h"
 #include "ash/aura/wm_lookup_aura.h"
 #include "ash/common/wm_shell.h"
@@ skipping 21 matching lines @@
 
   // WmShell:
   MruWindowTracker* GetMruWindowTracker() override;
   WmWindow* NewContainerWindow() override;
   WmWindow* GetFocusedWindow() override;
   WmWindow* GetActiveWindow() override;
   WmWindow* GetPrimaryRootWindow() override;
   WmWindow* GetRootWindowForDisplayId(int64_t display_id) override;
   WmWindow* GetRootWindowForNewWindows() override;
   bool IsForceMaximizeOnFirstRun() override;
+  bool IsPinned() override;
+  void SetPinnedWindow(WmWindow* window) override;
   bool CanShowWindowForUser(WmWindow* window) override;
   void LockCursor() override;
   void UnlockCursor() override;
   std::vector<WmWindow*> GetAllRootWindows() override;
   void RecordUserMetricsAction(UserMetricsAction action) override;
   std::unique_ptr<WindowResizer> CreateDragWindowResizer(
       std::unique_ptr<WindowResizer> next_window_resizer,
       wm::WindowState* window_state) override;
   void OnOverviewModeStarting() override;
   void OnOverviewModeEnded() override;
   bool IsOverviewModeSelecting() override;
   bool IsOverviewModeRestoringMinimizedWindows() override;
   AccessibilityDelegate* GetAccessibilityDelegate() override;
   SessionStateDelegate* GetSessionStateDelegate() override;
   void AddActivationObserver(WmActivationObserver* observer) override;
   void RemoveActivationObserver(WmActivationObserver* observer) override;
   void AddDisplayObserver(WmDisplayObserver* observer) override;
   void RemoveDisplayObserver(WmDisplayObserver* observer) override;
   void AddShellObserver(ShellObserver* observer) override;
   void RemoveShellObserver(ShellObserver* observer) override;
-  void NotifyPinnedStateChanged(WmWindow* pinned_window) override;
 
  private:
   // aura::client::ActivationChangeObserver:
   void OnWindowActivated(ActivationReason reason,
                          aura::Window* gained_active,
                          aura::Window* lost_active) override;
   void OnAttemptToReactivateWindow(aura::Window* request_active,
                                    aura::Window* actual_active) override;
 
   // WindowTreeHostManager::Observer:
   void OnDisplayConfigurationChanging() override;
   void OnDisplayConfigurationChanged() override;
 
   // Owned by Shell.
   WmShellCommon* wm_shell_common_;
 
   WmLookupAura wm_lookup_;
   bool added_activation_observer_ = false;
   base::ObserverList<WmActivationObserver> activation_observers_;
 
   bool added_display_observer_ = false;
   base::ObserverList<WmDisplayObserver> display_observers_;
 
   DISALLOW_COPY_AND_ASSIGN(WmShellAura);
 };
 
 }  // namespace ash
 
 #endif  // ASH_AURA_WM_SHELL_AURA_H_