Move screen capturers from remoting/capturer to media/video/capturer/screen

remoting/capturer/video_frame_capturer.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 REMOTING_CAPTURER_VIDEO_FRAME_CAPTURER_H_
-#define REMOTING_CAPTURER_VIDEO_FRAME_CAPTURER_H_
-
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "base/shared_memory.h"
-#include "third_party/skia/include/core/SkRegion.h"
-
-namespace remoting {
-
-class CaptureData;
-struct MouseCursorShape;
-class SharedBufferFactory;
-
-// Class used to capture video frames asynchronously.
-//
-// The full capture sequence is as follows:
-//
-// (1) Start
-//     This is when pre-capture steps are executed, such as flagging the
-//     display to prevent it from sleeping during a session.
-//
-// (2) InvalidateRegion
-//     This is an optional step where regions of the screen are marked as
-//     invalid. Some platforms (Windows, for now) won't use this and will
-//     instead calculate the diff-regions later (in step (2). Other
-//     platforms (Mac) will use this to mark all the changed regions of the
-//     screen. Some limited rect-merging (e.g., to eliminate exact
-//     duplicates) may be done here.
-//
-// (3) CaptureFrame
-//     This is where the bits for the invalid rects are packaged up and sent
-//     to the encoder.
-//     A screen capture is performed if needed. For example, Windows requires
-//     a capture to calculate the diff from the previous screen, whereas the
-//     Mac version does not.
-//
-// (4) Stop
-//     This is when post-capture steps are executed, such as releasing the
-//     assertion that prevents the display from sleeping.
-//
-// Implementation has to ensure the following guarantees:
-// 1. Double buffering
-//    Since data can be read while another capture action is happening.
-class VideoFrameCapturer {
- public:
-  // Provides callbacks used by the capturer to pass captured video frames and
-  // mouse cursor shapes to the processing pipeline.
-  class Delegate {
-   public:
-    virtual ~Delegate() {}
-
-    // Called when a video frame has been captured. |capture_data| describes
-    // a captured frame.
-    virtual void OnCaptureCompleted(
-        scoped_refptr<CaptureData> capture_data) = 0;
-
-    // Called when the cursor shape has changed.
-    // TODO(sergeyu): Move cursor shape capturing to a separate class.
-    virtual void OnCursorShapeChanged(
-        scoped_ptr<MouseCursorShape> cursor_shape) = 0;
-  };
-
-  virtual ~VideoFrameCapturer() {}
-
-  // Create platform-specific capturer.
-  static scoped_ptr<VideoFrameCapturer> Create();
-
-  // Create platform-specific capturer that uses shared memory buffers.
-  static scoped_ptr<VideoFrameCapturer> CreateWithFactory(
-      SharedBufferFactory* shared_buffer_factory);
-
-#if defined(OS_LINUX)
-  // Set whether the VideoFrameCapturer should try to use X DAMAGE support if it
-  // is available. This needs to be called before the VideoFrameCapturer is
-  // created.
-  // This is used by the Virtual Me2Me host, since the XDamage extension is
-  // known to work reliably in this case.
-
-  // TODO(lambroslambrou): This currently sets a global flag, referenced during
-  // VideoFrameCapturer::Create().  This is a temporary solution, until the
-  // DesktopEnvironment class is refactored to allow applications to control
-  // the creation of various stubs (including the VideoFrameCapturer) - see
-  // http://crbug.com/104544
-  static void EnableXDamage(bool enable);
-#endif  // defined(OS_LINUX)
-
-  // Called at the beginning of a capturing session. |delegate| must remain
-  // valid until Stop() is called.
-  virtual void Start(Delegate* delegate) = 0;
-
-  // Called at the end of a capturing session.
-  virtual void Stop() = 0;
-
-  // Invalidates the specified region.
-  virtual void InvalidateRegion(const SkRegion& invalid_region) = 0;
-
-  // Captures the screen data associated with each of the accumulated
-  // dirty region. When the capture is complete, the delegate is notified even
-  // if the dirty region is empty.
-  //
-  // It is OK to call this method while another thread is reading
-  // data of the previous capture. There can be at most one concurrent read
-  // going on when this method is called.
-  virtual void CaptureFrame() = 0;
-};
-
-}  // namespace remoting
-
-#endif  // REMOTING_CAPTURER_VIDEO_FRAME_CAPTURER_H_