Add video frame recording capability to Chromoting hosts.

remoting/host/video_frame_recorder_host_extension.h

Index: remoting/host/video_frame_recorder_host_extension.h
diff --git a/remoting/host/video_frame_recorder_host_extension.h b/remoting/host/video_frame_recorder_host_extension.h
new file mode 100644
index 0000000000000000000000000000000000000000..4a974e39ff5408aa6db3dae22d4b49f2d616585b
--- /dev/null
+++ b/remoting/host/video_frame_recorder_host_extension.h
@@ -0,0 +1,38 @@
+// Copyright 2014 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_VIDEO_FRAME_RECORDER_HOST_EXTENSION_H_
+#define REMOTING_HOST_VIDEO_FRAME_RECORDER_HOST_EXTENSION_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "remoting/host/host_extension.h"
+
+namespace remoting {
+
+// Extends Chromoting sessions with the ability to record raw frames and
+// download them to the client. This can be used to obtain representative
+// sequences of frames to run tests against.
+class VideoFrameRecorderHostExtension : public HostExtension {
+ public:
+  VideoFrameRecorderHostExtension() {}
+  virtual ~VideoFrameRecorderHostExtension() {}
+
+  // Sets the maximum number of bytes that each session may record.
+  void SetMaxContentBytes(int64_t max_content_bytes);

[Jamie, 2014/08/01 19:53:52]

If you can't pass max_content_bytes to the ctor, I think it would be safer to
initialize it to -1 and DCHECK in CreateExtensionSession to ensure that
SetMaxContentBytes has been called. The same might apply to the
VideoFrameRecorder class.

[Wez, 2014/08/01 22:33:56]

VideoFrameRecorder can actually be configured with a new buffer size on-the-fly,
including coping with the buffer size being dropped to zero.

The extension doesn't make use of that currently, nor do we re-configure it
after process startup, so I'll move the parameter to the ctor.

+
+  // remoting::HostExtension interface.
+  virtual std::string capability() const OVERRIDE;
+  virtual scoped_ptr<HostExtensionSession> CreateExtensionSession(
+      ClientSessionControl* client_session,
+      protocol::ClientStub* client_stub) OVERRIDE;
+
+ private:
+  int64_t max_content_bytes_;
+
+  DISALLOW_COPY_AND_ASSIGN(VideoFrameRecorderHostExtension);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_VIDEO_FRAME_RECORDER_HOST_EXTENSION_H_