Added video capture capabilities retrieval and caching to VideoCaptureManager

content/browser/renderer_host/media/video_capture_controller.cc

 // 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.
 
 #include "content/browser/renderer_host/media/video_capture_controller.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 126 matching lines @@
 VideoCaptureController::NewDeviceClient() {
   scoped_ptr<media::VideoCaptureDevice::Client> result(
       new VideoCaptureDeviceClient(this->GetWeakPtr(), buffer_pool_));
   return result.Pass();
 }
 
 void VideoCaptureController::AddClient(
     const VideoCaptureControllerID& id,
     VideoCaptureControllerEventHandler* event_handler,
     base::ProcessHandle render_process,
     const media::VideoCaptureParams& params) {

[ncarter (slow), 2013/11/12 20:56:46]

It might be slightly better to cache off just params.requested_format in this
function (making the new member a Format rather than a Params). The difference
being that a Controller can serve multiple session_ids at any given time, and so
it might not make sense to designate any as a controlling session.

[mcasas, 2013/11/13 11:40:37]

Done.

   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DVLOG(1) << "VideoCaptureController::AddClient, id " << id.device_id
            << ", (" << params.requested_format.width
            << ", " << params.requested_format.height
            << ", " << params.requested_format.frame_rate
            << ", " << params.session_id
            << ")";
 
+  video_capture_params_ = params;

[ncarter (slow), 2013/11/12 20:56:46]

It may make sense to update this only if it's the first client (params is a
request, and the policy implemented in VCM is that the first requesting client
gets its way). You could do this either by checking that the format in
video_capture_params_ is valid, or else by checking whether controller_clients_
is empty.

[mcasas, 2013/11/13 11:40:37]

Done.

+
   // Signal error in case device is already in error state.
   if (state_ == VIDEO_CAPTURE_STATE_ERROR) {
     event_handler->OnError(id);
     return;
   }
 
   // Do nothing if this client has called AddClient before.
   if (FindClient(id, event_handler, controller_clients_))
     return;
 
@@ skipping 56 matching lines @@
   // If this buffer is not held by this client, or this client doesn't exist
   // in controller, do nothing.
   if (!client || !client->active_buffers.erase(buffer_id)) {
     NOTREACHED();
     return;
   }
 
   buffer_pool_->RelinquishConsumerHold(buffer_id, 1);
 }
 
+const media::VideoCaptureParams&
+VideoCaptureController::GetVideoCaptureParams() const {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  return video_capture_params_;
+}
+
 scoped_refptr<media::VideoFrame>
 VideoCaptureController::VideoCaptureDeviceClient::ReserveOutputBuffer(
     const gfx::Size& size) {
   return DoReserveI420VideoFrame(size, 0);
 }
 
 void VideoCaptureController::VideoCaptureDeviceClient::OnIncomingCapturedFrame(
     const uint8* data,
     int length,
     base::Time timestamp,
@@ skipping 316 matching lines @@
   }
   return NULL;
 }
 
 int VideoCaptureController::GetClientCount() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   return controller_clients_.size();
 }
 
 }  // namespace content