[Device Service] Move Gamepad Blink headers to be part of the Gamepad client library

device/gamepad/gamepad_user_gesture.h

 // Copyright (c) 2012 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 DEVICE_GAMEPAD_USER_GESTURE_H_
 #define DEVICE_GAMEPAD_USER_GESTURE_H_
 
-namespace blink {
-class WebGamepads;
-}
+namespace device {
 
-namespace device {
+class Gamepads;
 
 // Returns true if any of the gamepads have a button pressed or axis moved
 // that would be considered a user gesture for interaction.
-bool GamepadsHaveUserGesture(const blink::WebGamepads& gamepads);
+bool GamepadsHaveUserGesture(const Gamepads& gamepads);
 
 }  // namespace device
 
 #endif  // DEVICE_GAMEPAD_USER_GESTURE_H_