Migrate WTF::Vector::append() to ::push_back() [part 13 of N]

third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp

Index: third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
diff --git a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
index c78480d18415b33a72b82d9c78abcfa215f58b39..d5b9798caef186e59a3d43abf0c278397cdc986a 100644
--- a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
+++ b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
@@ -772,11 +772,11 @@ bool SourceBuffer::initializationSegmentReceived(
   for (const MediaTrackInfo& trackInfo : newTracks) {
     const TrackBase* track = nullptr;
     if (trackInfo.trackType == WebMediaPlayer::AudioTrack) {
-      newAudioTracks.append(trackInfo);
+      newAudioTracks.push_back(trackInfo);
       if (m_firstInitializationSegmentReceived)
         track = findExistingTrackById(audioTracks(), trackInfo.id);
     } else if (trackInfo.trackType == WebMediaPlayer::VideoTrack) {
-      newVideoTracks.append(trackInfo);
+      newVideoTracks.push_back(trackInfo);
       if (m_firstInitializationSegmentReceived)
         track = findExistingTrackById(videoTracks(), trackInfo.id);
     } else {