enable video capture to support sharing across multiple renderer processes

media/video/capture/linux/video_capture_device_linux.cc

Index: media/video/capture/linux/video_capture_device_linux.cc
===================================================================
--- media/video/capture/linux/video_capture_device_linux.cc	(revision 105502)
+++ media/video/capture/linux/video_capture_device_linux.cc	(working copy)
@@ -192,6 +192,7 @@
   DCHECK_EQ(v4l2_thread_.message_loop(), MessageLoop::current());
 
   observer_ = observer;
+  observer_->OnDeviceState(true);

[perkj_chrome, 2011/10/17 08:39:43]

What is the purpose of this? Is it possible to avoid. You know you will have to
change this on all platforms.

[wjia(left Chromium), 2011/10/21 00:56:13]

I am trying to handle the case where observer_ (i.e., VCController) has been
deleted, but device still calls its function. With this signal, manager knows
when to delete controller safely.

[perkj_chrome, 2011/10/21 14:54:00]

We had previously solved this in another way.
Also VideoCapture::Stop is syncronouse. So after calling Stop the device will
not call the VC controller.


On 2011/10/21 00:56:13, wjia wrote:

[wjia(left Chromium), 2011/10/21 23:54:16]

Could you clarify it's VideoCapture::StopCapture or VideoCaptureDevice::Stop,
since VideoCapture::Stop doesn't exist. Neither one is synchronous though. See
media/video/capture/linux/video_capture_device_linux.cc and
content/renderer/media/video_capture_impl.cc.


On 2011/10/21 14:54:00, perkj wrote:

 
   if ((device_fd_ = open(device_name_.unique_id.c_str(), O_RDONLY)) < 0) {
     SetErrorState("Failed to open V4L2 device driver.");
@@ -442,6 +443,7 @@
   delete [] buffer_pool_;
   buffer_pool_ = NULL;
   buffer_pool_size_ = 0;
+  observer_->OnDeviceState(false);
 }
 
 void VideoCaptureDeviceLinux::SetErrorState(const std::string& reason) {