content/browser/media/capture/web_contents_video_capture_device.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_
   6 #define CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "content/common/content_export.h"
  12 #include "media/capture/content/screen_capture_device_core.h"
  13 #include "media/capture/video/video_capture_device.h"
  14
  15 namespace content {
  16
  17 // A virtualized VideoCaptureDevice that mirrors the displayed contents of a
  18 // WebContents (i.e., the composition of an entire render frame tree), producing
  19 // a stream of video frames.
  20 //
  21 // An instance is created by providing a device_id.  The device_id contains
  22 // information necessary for finding a WebContents instance.  From then on,
  23 // WebContentsVideoCaptureDevice will capture from the RenderWidgetHost that
  24 // encompasses the currently active RenderFrameHost tree for that that
  25 // WebContents instance.  As the RenderFrameHost tree mutates (e.g., due to page
  26 // navigations, or crashes/reloads), capture will continue without interruption.
  27 class CONTENT_EXPORT WebContentsVideoCaptureDevice
  28     : public media::VideoCaptureDevice {
  29  public:
  30   // Create a WebContentsVideoCaptureDevice instance from the given
  31   // |device_id|.  Returns NULL if |device_id| is invalid.
  32   static media::VideoCaptureDevice* Create(const std::string& device_id);
  33
  34   ~WebContentsVideoCaptureDevice() override;
  35
  36   // VideoCaptureDevice implementation.
  37   void AllocateAndStart(const media::VideoCaptureParams& params,
  38                         scoped_ptr<Client> client) override;
  39   void StopAndDeAllocate() override;
  40
  41  private:
  42   WebContentsVideoCaptureDevice(
  43       int render_process_id,
  44       int main_render_frame_id,
  45       bool enable_auto_throttling);
  46
  47   const scoped_ptr<media::ScreenCaptureDeviceCore> core_;
  48
  49   DISALLOW_COPY_AND_ASSIGN(WebContentsVideoCaptureDevice);
  50 };
  51
  52
  53 }  // namespace content
  54
  55 #endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_