Basic use implementation for MediaStream from Canvas: captureStream()

content/renderer/media/canvas_capture_handler.h

+// Copyright 2015 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_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_
+#define CONTENT_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
+#include "content/common/content_export.h"
+#include "media/base/video_capturer_source.h"
+#include "media/base/video_frame_pool.h"
+#include "third_party/WebKit/public/platform/WebCanvasCaptureHandler.h"
+#include "third_party/WebKit/public/platform/WebMediaStream.h"
+#include "third_party/WebKit/public/platform/WebSize.h"
+#include "third_party/WebKit/public/platform/WebSkImage.h"
+#include "third_party/skia/include/core/SkImage.h"
+
+namespace content {
+
+class CONTENT_EXPORT CanvasCaptureHandler final
+    : public NON_EXPORTED_BASE(blink::WebCanvasCaptureHandler) {
+ public:
+  CanvasCaptureHandler(const blink::WebSize& size,
+                       double frame_rate,
+                       blink::WebMediaStream* stream);
+
+  // blink::WebCanvasCaptureHandler Implementation.
+  void sendNewFrame(const blink::WebSkImage& image) override;
+  bool needsNewFrameCapture() const override;
+
+  // Functions called by media::VideoCapturerSource implementation.
+  void StartVideoCapture(
+      const media::VideoCaptureParams& params,
+      const media::VideoCapturerSource::VideoCaptureDeliverFrameCB&
+          new_frame_callback,
+      const media::VideoCapturerSource::RunningCallback& running_callback);
+  void StopVideoCapture();
+  blink::WebSize GetSourceSize() const { return size_; }
+  double GetSourceFrameRate() const { return frame_rate_; }
+
+ private:
+  virtual ~CanvasCaptureHandler();
+
+  void CreateNewFrame(const blink::WebSkImage& image);
+
+  // Implementation VideoCapturerSource that is owned by blink and delegates
+  // the Start/Stop calls to CanvasCaptureHandler.
+  class VideoCapturerSource;
+  // Object that does all the work of running |new_frame_callback_|.
+  // Destroyed on |io_task_runner_| after the class is destroyed.
+  class CanvasCaptureHandlerDelegate;
+
+  media::VideoCaptureFormat capture_format_;
+  double frame_rate_;
+  bool ask_for_new_frame_;
+
+  const blink::WebSize size_;
+  gfx::Size last_size;
+  std::vector<uint8> temp_data_;
+  size_t row_bytes_;
+  SkImageInfo image_info_;
+  media::VideoFramePool frame_pool_;
+
+  const scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
+  scoped_ptr<CanvasCaptureHandlerDelegate> delegate_;
+  // Bound to the main render thread.
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(CanvasCaptureHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_CANVAS_CAPTURE_HANDLER_H_