Linux video capture: handle devices that don't enumerate any frame rates

BUG=412284
TEST=Check output from DVLOG(1) << device.name() << " " << supported_format.ToString() in VideoCaptureDeviceFactoryLinux::GetDeviceSupportedFormats. For a Kinect Camera, it will now list: Microsoft Kinect Camera resolution: 640x480, fps: 0.000000, pixel format: UYUY

Review URL: https://codereview.chromium.org/544033002

Cr-Commit-Position: refs/heads/master@{#293923}

media/video/capture/linux/video_capture_device_factory_linux.cc

@@ -155,15 +155,14 @@ void VideoCaptureDeviceFactoryLinux::GetDeviceSupportedFormats(
       frame_interval.pixel_format = pixel_format.pixelformat;
       frame_interval.width = frame_size.discrete.width;
       frame_interval.height = frame_size.discrete.height;
+      std::list<float> frame_rates;
       while (HANDLE_EINTR(ioctl(
                  fd.get(), VIDIOC_ENUM_FRAMEINTERVALS, &frame_interval)) == 0) {
         if (frame_interval.type == V4L2_FRMIVAL_TYPE_DISCRETE) {
           if (frame_interval.discrete.numerator != 0) {
-            supported_format.frame_rate =
+            frame_rates.push_back(
                 static_cast<float>(frame_interval.discrete.denominator) /
-                static_cast<float>(frame_interval.discrete.numerator);
-          } else {
-            supported_format.frame_rate = 0;
+                static_cast<float>(frame_interval.discrete.numerator));
           }
         } else if (frame_interval.type == V4L2_FRMIVAL_TYPE_CONTINUOUS) {
           // TODO(mcasas): see http://crbug.com/249953, support these devices.
@@ -174,9 +173,20 @@ void VideoCaptureDeviceFactoryLinux::GetDeviceSupportedFormats(
           NOTIMPLEMENTED();
           break;
         }
+        ++frame_interval.index;
+      }
+
+      // Some devices, e.g. Kinect, do not enumerate any frame rates. For these
+      // devices, we do not want to lose all enumeration (pixel format and
+      // resolution), so we return a frame rate of zero instead.
+      if (frame_rates.empty())
+        frame_rates.push_back(0);
+
+      for (std::list<float>::iterator it = frame_rates.begin();
+           it != frame_rates.end(); ++it) {
+        supported_format.frame_rate = *it;
         supported_formats->push_back(supported_format);
         DVLOG(1) << device.name() << " " << supported_format.ToString();
-        ++frame_interval.index;
       }
       ++frame_size.index;
     }

media/video/capture/linux/video_capture_device_linux.cc

@@ -204,7 +204,7 @@ void VideoCaptureDeviceLinux::SetRotationOnV4L2Thread(int rotation) {
 
 void VideoCaptureDeviceLinux::OnAllocateAndStart(int width,
                                                  int height,
-                                                 int frame_rate,
+                                                 float frame_rate,
                                                  scoped_ptr<Client> client) {
   DCHECK_EQ(v4l2_thread_.message_loop(), base::MessageLoop::current());
 

media/video/capture/linux/video_capture_device_linux.h

@@ -59,7 +59,7 @@ class VideoCaptureDeviceLinux : public VideoCaptureDevice {
   // Called on the v4l2_thread_.
   void OnAllocateAndStart(int width,
                           int height,
-                          int frame_rate,
+                          float frame_rate,
                           scoped_ptr<Client> client);
   void OnStopAndDeAllocate();
   void OnCaptureTask();