remoting/host: Rename Capturer to VideoFrameCapturer.

remoting/host/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_HOST_CAPTURER_H_
-#define REMOTING_HOST_CAPTURER_H_
-
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "media/base/video_frame.h"
-#include "third_party/skia/include/core/SkRegion.h"
-
-namespace remoting {
-
-namespace protocol {
-class CursorShapeInfo;
-}
-
-class CaptureData;
-
-// A class to perform the task of capturing the image of a window.
-// The capture action is asynchronous to allow maximum throughput.
-//
-// The full capture process 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) InvalidateRects
-//     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) CaptureInvalidRects
-//     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 Capturer {
- public:
-  // CaptureCompletedCallback is called when the capturer has completed.
-  typedef base::Callback<void(scoped_refptr<CaptureData>)>
-      CaptureCompletedCallback;
-
-  // CursorShapeChangedCallback is called when the cursor shape has changed.
-  typedef base::Callback<void(scoped_ptr<protocol::CursorShapeInfo>)>
-      CursorShapeChangedCallback;
-
-  virtual ~Capturer() {};
-
-  // Create platform-specific capturer.
-  static Capturer* Create();
-
-#if defined(OS_LINUX)
-  // Set whether the Capturer should try to use X DAMAGE support if it is
-  // available.  This needs to be called before the Capturer 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
-  // Capturer::Create().  This is a temporary solution, until the
-  // DesktopEnvironment class is refactored to allow applications to control
-  // the creation of various stubs (including the Capturer) - see
-  // http://crbug.com/104544
-  static void EnableXDamage(bool enable);
-#endif  // defined(OS_LINUX)
-
-  // Called at the beginning of a capturing session.
-  virtual void Start(
-      const CursorShapeChangedCallback& callback) = 0;
-
-  // Called at the end of a capturing session.
-  virtual void Stop() = 0;
-
-  // Called when the screen configuration is changed.
-  virtual void ScreenConfigurationChanged() = 0;
-
-  // Return the pixel format of the screen.
-  virtual media::VideoFrame::Format pixel_format() const = 0;
-
-  // Clear out the invalid region.
-  virtual void ClearInvalidRegion() = 0;
-
-  // Invalidate the specified region.
-  virtual void InvalidateRegion(const SkRegion& invalid_region) = 0;
-
-  // Invalidate the entire screen, of a given size.
-  virtual void InvalidateScreen(const SkISize& size) = 0;
-
-  // Invalidate the entire screen, using the size of the most recently
-  // captured screen.
-  virtual void InvalidateFullScreen() = 0;
-
-  // Capture the screen data associated with each of the accumulated
-  // dirty region.
-  // When the capture is complete, |callback| is called 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 CaptureInvalidRegion(
-      const CaptureCompletedCallback& callback) = 0;
-
-  // Get the size of the most recently captured screen.
-  virtual const SkISize& size_most_recent() const = 0;
-};
-
-}  // namespace remoting
-
-#endif  // REMOTING_HOST_CAPTURER_H_