Remove VideoFrameType aliases for FrameType.

No longer used in Chromium, so these can now be removed.

BUG=webrtc:5042
R=mflodman@webrtc.org
TBR=magjed@webrtc.org

Review URL: https://codereview.webrtc.org/1415693002 .

Cr-Commit-Position: refs/heads/master@{#10390}

webrtc/modules/video_coding/main/source/encoded_frame.cc

@@ -89,7 +89,7 @@ void VCMEncodedFrame::Reset()
     _renderTimeMs = -1;
     _timeStamp = 0;
     _payloadType = 0;
-    _frameType = kDeltaFrame;
+    _frameType = kVideoFrameDelta;
     _encodedWidth = 0;
     _encodedHeight = 0;
     _completeFrame = false;