Revert of Stop caching supported codecs in WebRtcVideoEngine2

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 dfdae5ea99ad13ba2122f6465adf8dea6f94b8f8..3cacc7da82ba3ee32cdfa69abf271635df9ec98b 100644
--- a/webrtc/media/engine/webrtcvideoengine2.cc
+++ b/webrtc/media/engine/webrtcvideoengine2.cc
@@ -543,6 +543,7 @@
       external_decoder_factory_(NULL),
       external_encoder_factory_(NULL) {
   LOG(LS_INFO) << "WebRtcVideoEngine2::WebRtcVideoEngine2()";
+  video_codecs_ = GetSupportedCodecs(external_encoder_factory_);
 }
 
 WebRtcVideoEngine2::~WebRtcVideoEngine2() {
@@ -565,8 +566,8 @@
                                  external_decoder_factory_);
 }
 
-const std::vector<VideoCodec> WebRtcVideoEngine2::codecs() const {
-  return GetSupportedCodecs(external_encoder_factory_);
+const std::vector<VideoCodec>& WebRtcVideoEngine2::codecs() const {
+  return video_codecs_;
 }
 
 RtpCapabilities WebRtcVideoEngine2::GetCapabilities() const {
@@ -613,6 +614,8 @@
     encoder_factory = simulcast_encoder_factory_.get();
   }
   external_encoder_factory_ = encoder_factory;
+
+  video_codecs_ = GetSupportedCodecs(encoder_factory);
 }
 
 static std::vector<VideoCodec> GetSupportedCodecs(