Apply toFoo generation macro to TrackBase classes

Source/bindings/core/v8/custom/V8TrackEventCustom.cpp

Index: Source/bindings/core/v8/custom/V8TrackEventCustom.cpp
diff --git a/Source/bindings/core/v8/custom/V8TrackEventCustom.cpp b/Source/bindings/core/v8/custom/V8TrackEventCustom.cpp
index 9c2b04e3c31863545e3f3edee7a028b9b11c79ca..f70db0945114ebf669cbb11aa1f39a92e4bd506d 100644
--- a/Source/bindings/core/v8/custom/V8TrackEventCustom.cpp
+++ b/Source/bindings/core/v8/custom/V8TrackEventCustom.cpp
@@ -51,15 +51,15 @@ void V8TrackEvent::trackAttributeGetterCustom(const v8::PropertyCallbackInfo<v8:
 
     switch (track->type()) {
     case TrackBase::TextTrack:
-        v8SetReturnValueFast(info, static_cast<TextTrack*>(track), trackEvent);
+        v8SetReturnValueFast(info, toTextTrack(track), trackEvent);
         return;
 
     case TrackBase::AudioTrack:
-        v8SetReturnValueFast(info, static_cast<AudioTrack*>(track), trackEvent);
+        v8SetReturnValueFast(info, toAudioTrack(track), trackEvent);
         return;
 
     case TrackBase::VideoTrack:
-        v8SetReturnValueFast(info, static_cast<VideoTrack*>(track), trackEvent);
+        v8SetReturnValueFast(info, toVideoTrack(track), trackEvent);
         return;
     }