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 106642)
+++ 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, 2011/10/21 14:54:00]

Still think you should remove this.

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

We can discuss it after you confirm whether VideoCaptureDevice::Stop is sync or
async mode.

 
   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) {