Remove VIDEOCODEC_* from engine_configurations.h.

Removes index-based codec fetching from the VCM and overall cleans up
the code.

BUG=webrtc:1695
R=mflodman@webrtc.org

Review URL: https://codereview.webrtc.org/1425613004 .

Cr-Commit-Position: refs/heads/master@{#10770}
diff --git a/webrtc/modules/video_coding/video_coding_impl.cc b/webrtc/modules/video_coding/video_coding_impl.cc
index 6d1151a..1b6a893 100644
--- a/webrtc/modules/video_coding/video_coding_impl.cc
+++ b/webrtc/modules/video_coding/video_coding_impl.cc
@@ -309,22 +309,9 @@
 };
 }  // namespace
 
-uint8_t VideoCodingModule::NumberOfCodecs() {
-  return VCMCodecDataBase::NumberOfCodecs();
-}
-
-int32_t VideoCodingModule::Codec(uint8_t listId, VideoCodec* codec) {
-  if (codec == NULL) {
-    return VCM_PARAMETER_ERROR;
-  }
-  return VCMCodecDataBase::Codec(listId, codec) ? 0 : -1;
-}
-
 int32_t VideoCodingModule::Codec(VideoCodecType codecType, VideoCodec* codec) {
-  if (codec == NULL) {
-    return VCM_PARAMETER_ERROR;
-  }
-  return VCMCodecDataBase::Codec(codecType, codec) ? 0 : -1;
+  VCMCodecDataBase::Codec(codecType, codec);
+  return 0;
 }
 
 VideoCodingModule* VideoCodingModule::Create(