cricket::VideoFrame cleanup. New width() and height(). Deleted GetChroma* methods.

webrtc/api/objc/RTCVideoFrame.mm

Index: webrtc/api/objc/RTCVideoFrame.mm
diff --git a/webrtc/api/objc/RTCVideoFrame.mm b/webrtc/api/objc/RTCVideoFrame.mm
index db2d07ba31a82a1e8371529cc5ff22592a42034e..ddb2dbca0bf44e7affcfce0a9a8ebd33297be0b8 100644
--- a/webrtc/api/objc/RTCVideoFrame.mm
+++ b/webrtc/api/objc/RTCVideoFrame.mm
@@ -19,23 +19,19 @@
 }
 
 - (size_t)width {
-  return _videoFrame->GetWidth();
+  return _videoFrame->width();
 }
 
 - (size_t)height {
-  return _videoFrame->GetHeight();
+  return _videoFrame->height();
 }
 
 - (size_t)chromaWidth {
-  return _videoFrame->GetChromaWidth();
+  return (self.width + 1) / 2;
 }
 
 - (size_t)chromaHeight {
-  return _videoFrame->GetChromaHeight();
-}
-
-- (size_t)chromaSize {
-  return _videoFrame->GetChromaSize();
+  return (self.height + 1) / 2;
 }
 
 - (const uint8_t *)yPlane {