cros: Bind password echo with TouchView mode

chrome/browser/chromeos/ui/password_echo_controller.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 CHROME_BROWSER_CHROMEOS_UI_PASSWORD_ECHO_CONTROLLER_H_
+#define CHROME_BROWSER_CHROMEOS_UI_PASSWORD_ECHO_CONTROLLER_H_
+
+#include "ash/common/shell_observer.h"
+#include "base/macros.h"
+
+namespace chromeos {
+
+// Manages password echo behavior for renderers and TextFields. The current
+// behavior is to enable password echo when TouchView mode is on and disable
+// it when TouchView mode is off.
+class PasswordEchoController : ash::ShellObserver {
+ public:
+  PasswordEchoController();
+  ~PasswordEchoController() override;
+
+  // Gets the current instance. Returns nullptr if there is no current instance.
+  static PasswordEchoController* Get();
+
+  bool enabled() const { return enabled_; }
+
+ private:
+  void SetEnabled(bool enabled);
+  void UpdateWebkitPreferences();
+
+  // ash::ShellObserver
+  void OnMaximizeModeStarted() override;
+  void OnMaximizeModeEnded() override;
+
+  // Whether password echo is enabled.
+  bool enabled_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(PasswordEchoController);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_UI_PASSWORD_ECHO_CONTROLLER_H_