[H264][Simulcast] Implement the simulcast logic for h264 encoder

webrtc/media/engine/webrtcvideoengine2.cc

Index: webrtc/media/engine/webrtcvideoengine2.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2.cc b/webrtc/media/engine/webrtcvideoengine2.cc
index 383f29a9228250f4ab9fa171802e1da8f586ca19..bd36be5c86c27ec3faffb9d5da115736eecaaafe 100644
--- a/webrtc/media/engine/webrtcvideoengine2.cc
+++ b/webrtc/media/engine/webrtcvideoengine2.cc
@@ -296,8 +296,7 @@ static void MergeFecConfig(const webrtc::FecConfig& other,
 
 // Returns true if the given codec is disallowed from doing simulcast.
 bool IsCodecBlacklistedForSimulcast(const std::string& codec_name) {
-  return CodecNamesEq(codec_name, kH264CodecName) ||
-         CodecNamesEq(codec_name, kVp9CodecName);
+  return CodecNamesEq(codec_name, kVp9CodecName);
 }
 
 // The selected thresholds for QVGA and VGA corresponded to a QP around 10.