Remove keyboard usability mode

ui/keyboard/keyboard_util.h

 // Copyright (c) 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.
 
 #ifndef UI_KEYBOARD_KEYBOARD_UTIL_H_
 #define UI_KEYBOARD_KEYBOARD_UTIL_H_
 
 #include <string>
 
 #include "base/strings/string16.h"
@@ skipping 61 matching lines @@
 
 // Gets the state of the touch onscreen keyboard.
 KEYBOARD_EXPORT bool GetTouchKeyboardEnabled();
 
 // Gets the default keyboard layout.
 KEYBOARD_EXPORT std::string GetKeyboardLayout();
 
 // Returns true if the virtual keyboard is enabled.
 KEYBOARD_EXPORT bool IsKeyboardEnabled();
 
-// Returns true if the keyboard usability test is enabled.
-KEYBOARD_EXPORT bool IsKeyboardUsabilityExperimentEnabled();
-
 // Returns true if keyboard overscroll mode is enabled.
 KEYBOARD_EXPORT bool IsKeyboardOverscrollEnabled();
 
 // Sets temporary keyboard overscroll override.
 KEYBOARD_EXPORT void SetKeyboardOverscrollOverride(
     KeyboardOverscrolOverride override);
 
 // Sets policy override on whether to show the keyboard.
 KEYBOARD_EXPORT void SetKeyboardShowOverride(KeyboardShowOverride override);
 
@@ skipping 50 matching lines @@
 
 // Gets the override content url.
 KEYBOARD_EXPORT const GURL& GetOverrideContentUrl();
 
 // Logs the keyboard control event as a UMA stat.
 void LogKeyboardControlEvent(KeyboardControlEvent event);
 
 }  // namespace keyboard
 
 #endif  // UI_KEYBOARD_KEYBOARD_UTIL_H_