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/video/capture/video_capture_device.h"
  13
  14 namespace content {
  15
  16 class ContentVideoCaptureDeviceCore;
  17
  18 // A virtualized VideoCaptureDevice that mirrors the displayed contents of a
  19 // WebContents (i.e., the composition of an entire render frame tree), producing
  20 // a stream of video frames.
  21 //
  22 // An instance is created by providing a device_id.  The device_id contains
  23 // information necessary for finding a WebContents instance.  From then on,
  24 // WebContentsVideoCaptureDevice will capture from the RenderWidgetHost that
  25 // encompasses the currently active RenderFrameHost tree for that that
  26 // WebContents instance.  As the RenderFrameHost tree mutates (e.g., due to page
  27 // navigations, or crashes/reloads), capture will continue without interruption.
  28 class CONTENT_EXPORT WebContentsVideoCaptureDevice
  29     : public media::VideoCaptureDevice {
  30  public:
  31   // Create a WebContentsVideoCaptureDevice instance from the given
  32   // |device_id|.  Returns NULL if |device_id| is invalid.
  33   static media::VideoCaptureDevice* Create(const std::string& device_id);
  34
  35   ~WebContentsVideoCaptureDevice() override;
  36
  37   // VideoCaptureDevice implementation.
  38   void AllocateAndStart(const media::VideoCaptureParams& params,
  39                         scoped_ptr<Client> client) override;
  40   void StopAndDeAllocate() override;
  41
  42  private:
  43   WebContentsVideoCaptureDevice(
  44       int render_process_id, int main_render_frame_id);
  45
  46   const scoped_ptr<ContentVideoCaptureDeviceCore> core_;
  47
  48   DISALLOW_COPY_AND_ASSIGN(WebContentsVideoCaptureDevice);
  49 };
  50
  51
  52 }  // namespace content
  53
  54 #endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_VIDEO_CAPTURE_DEVICE_H_