Handle UNPIN operation in ash.

ash/accelerators/accelerator_commands.cc

 // Copyright 2013 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.
 
 #include "ash/accelerators/accelerator_commands.h"
 
 #include "ash/common/wm/mru_window_tracker.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/common/wm/wm_event.h"
 #include "ash/common/wm_window.h"
 #include "ash/display/display_manager.h"
 #include "ash/display/display_util.h"
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
+#include "ash/wm/screen_pinning_controller.h"
 #include "ash/wm/window_state_aura.h"
 #include "ash/wm/window_util.h"
 #include "base/metrics/user_metrics.h"
 
 namespace ash {
 namespace accelerators {
 
 bool ToggleMinimized() {
   aura::Window* window = wm::GetActiveWindow();
   // Attempt to restore the window that would be cycled through next from
@@ skipping 75 matching lines @@
     const std::vector<DisplayMode>& modes = display_info.display_modes();
     auto iter =
         std::find_if(modes.begin(), modes.end(),
                      [](const DisplayMode& mode) { return mode.native; });
     display_manager->SetDisplayMode(DisplayManager::kUnifiedDisplayId, *iter);
   } else {
     SetDisplayUIScale(display_manager->GetDisplayIdForUIScaling(), 1.0f);
   }
 }
 
+void Unpin() {
+  WmWindow* pinned_window =
+      Shell::GetInstance()->screen_pinning_controller()->pinned_window();
+  if (pinned_window)
+    pinned_window->GetWindowState()->Restore();
+}
+
 }  // namespace accelerators
 }  // namespace ash