Add VideoCaptureDevice::GetDeviceSupportedFormats to interface + implementation for Linux and Fake

media/video/capture/linux/video_capture_device_linux.cc

Index: media/video/capture/linux/video_capture_device_linux.cc
diff --git a/media/video/capture/linux/video_capture_device_linux.cc b/media/video/capture/linux/video_capture_device_linux.cc
index b7a2e137ea9e42273c9636a82770f0f87e7314f2..24999b8d3ef6b4f54491b0548ef1de35c7becc52 100644
--- a/media/video/capture/linux/video_capture_device_linux.cc
+++ b/media/video/capture/linux/video_capture_device_linux.cc
@@ -141,6 +141,77 @@ void VideoCaptureDevice::GetDeviceNames(Names* device_names) {
   }
 }
 
+void VideoCaptureDevice::GetDeviceSupportedFormats(
+    const Name& device,
+    VideoCaptureFormats* formats) {
+
+  if (device.id().empty())
+    return;
+  int fd;
+  VideoCaptureFormats capture_formats;
+  if ((fd = open(device.id().c_str(), O_RDONLY)) < 0) {
+    // Failed to open this device.
+    return;
+  }
+
+  formats->clear();
+
+  VideoCaptureCapability capture_format;
+  // Retrieve the caps one by one, first get colorspace, then sizes, then
+  // framerates. See http://linuxtv.org/downloads/v4l-dvb-apis for reference.
+  v4l2_fmtdesc pixel_format = {};
+  pixel_format.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+  while (ioctl(fd, VIDIOC_ENUM_FMT, &pixel_format) == 0) {
+    capture_format.color =
+        V4l2ColorToVideoCaptureColorFormat((int32)pixel_format.pixelformat);

[perkj_chrome, 2013/10/15 08:42:54]

If you look at V4l2ColorToVideoCaptureColorFormat - it only support a very
limited set for color spaces. So this will DCHECK on a number of devices. 
Please change this to just print out the formats we don't support and make sure
they are not added to |formats|. (interestingly I don't see this function being
used at all previously).

[mcasas, 2013/10/15 11:32:09]

Added the remaining colourspaces to V4l2...(); added a check in this line to
skip unknown colorspaces.

+
+    v4l2_frmsizeenum frame_size = {};
+    frame_size.pixel_format = pixel_format.pixelformat;
+    while (ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &frame_size) == 0) {
+      if (frame_size.type == V4L2_FRMSIZE_TYPE_DISCRETE) {
+        capture_format.width = frame_size.discrete.width;
+        capture_format.height = frame_size.discrete.height;
+      } else if (frame_size.type == V4L2_FRMSIZE_TYPE_STEPWISE) {
+        // TODO(mcasas): see http://crbug.com/249953, support these devices.
+        NOTIMPLEMENTED();
+      } else if (frame_size.type == V4L2_FRMSIZE_TYPE_CONTINUOUS) {
+        // TODO(mcasas): see http://crbug.com/249953, support these devices.
+        NOTIMPLEMENTED();
+      }
+      v4l2_frmivalenum frame_interval = {};
+      frame_interval.pixel_format = pixel_format.pixelformat;
+      frame_interval.width = frame_size.discrete.width;
+      frame_interval.height = frame_size.discrete.height;
+      while (ioctl(fd, VIDIOC_ENUM_FRAMEINTERVALS, &frame_interval) == 0) {
+        if (frame_interval.type == V4L2_FRMIVAL_TYPE_DISCRETE) {
+          if (frame_interval.discrete.numerator != 0) {
+            capture_format.frame_rate =
+                static_cast<float>(frame_interval.discrete.denominator) /
+                static_cast<float>(frame_interval.discrete.numerator);
+          } else {
+            capture_format.frame_rate = 0;
+          }
+        } else if (frame_interval.type == V4L2_FRMIVAL_TYPE_CONTINUOUS) {
+          // TODO(mcasas): see http://crbug.com/249953, support these devices.
+          NOTIMPLEMENTED();
+          break;
+        } else if (frame_interval.type == V4L2_FRMIVAL_TYPE_STEPWISE) {
+          // TODO(mcasas): see http://crbug.com/249953, support these devices.
+          NOTIMPLEMENTED();
+          break;
+        }
+        formats->push_back(capture_format);
+        ++frame_interval.index;
+      }
+      ++frame_size.index;
+    }
+    ++pixel_format.index;
+  }
+
+  close(fd);
+  return;
+}
+
 static bool ReadIdFile(const std::string path, std::string* id) {
   char id_buf[kVidPidSize];
   FILE* file = fopen(path.c_str(), "rb");