cros: Preload and reuse the lock screen across lock sessions

chrome/browser/chromeos/login/lock/webui_screen_locker.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 CHROME_BROWSER_CHROMEOS_LOGIN_LOCK_WEBUI_SCREEN_LOCKER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_LOCK_WEBUI_SCREEN_LOCKER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 37 matching lines @@
 class WebUIScreenLocker : public WebUILoginView,
                           public LoginDisplay::Delegate,
                           public ash::LockStateObserver,
                           public views::WidgetObserver,
                           public PowerManagerClient::Observer,
                           public ash::ShellObserver,
                           public keyboard::KeyboardControllerObserver,
                           public display::DisplayObserver,
                           public content::WebContentsObserver {
  public:
+  // Returns true if the lock screen should be shared.
+  static bool ShouldShareLockScreen();
+  static void Preload();
+
   explicit WebUIScreenLocker(ScreenLocker* screen_locker);
   ~WebUIScreenLocker() override;
 
   // Begin initializing the widget and views::WebView that show the lock screen.
   // ScreenLockReady is called when all initialization has finished.
   void LockScreen();
 
   // Enable/disable password input.
   void SetInputEnabled(bool enabled);
 
@@ skipping 113 matching lines @@
   bool is_observing_keyboard_ = false;
 
   base::WeakPtrFactory<WebUIScreenLocker> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebUIScreenLocker);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_LOCK_WEBUI_SCREEN_LOCKER_H_