sensors: Remove prototype implementation

content/public/browser/sensors.h

-// Copyright (c) 2011 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 CONTENT_PUBLIC_BROWSER_SENSORS_H_
-#define CONTENT_PUBLIC_BROWSER_SENSORS_H_
-#pragma once
-
-// The sensors API will unify various types of sensor data into a set of
-// channels, each of which provides change events and periodic updates.
-//
-// This version of the API is intended only to support the experimental screen
-// rotation code and is not for general use.
-
-namespace content {
-
-// The side of the device which the user probably perceives as facing upward.
-// This can be used to orient controls and content in a "natural" direction.
-enum ScreenOrientation {
-  SCREEN_ORIENTATION_TOP = 0,     // The screen is in its normal orientation.
-  // The screen is upside-down (180-degree rotation).
-  SCREEN_ORIENTATION_BOTTOM = 1,
-  SCREEN_ORIENTATION_LEFT = 2,    // The right side of the screen is at the top.
-  SCREEN_ORIENTATION_RIGHT = 3,   // The left side of the screen is at the top.
-  SCREEN_ORIENTATION_FRONT = 4,   // The screen is laid flat, facing upward.
-  SCREEN_ORIENTATION_BACK = 5     // The screen is laid flat, facing downward.
-};
-
-}  // namespace content
-
-#endif  // CONTENT_PUBLIC_BROWSER_SENSORS_H_