Add [TypeChecking=Interface] to the TextTrack interface

Source/core/html/track/TextTrack.cpp

Index: Source/core/html/track/TextTrack.cpp
diff --git a/Source/core/html/track/TextTrack.cpp b/Source/core/html/track/TextTrack.cpp
index 54f2cbdec176b2a2c6a4aefe59f6fb5adc5abd34..04fda3c362a2baa1dbbf86be57c5deee8e75e374 100644
--- a/Source/core/html/track/TextTrack.cpp
+++ b/Source/core/html/track/TextTrack.cpp
@@ -225,9 +225,7 @@ TextTrackCueList* TextTrack::activeCues() const
 
 void TextTrack::addCue(PassRefPtrWillBeRawPtr<TextTrackCue> prpCue)
 {
-    if (!prpCue)
-        return;
-
+    ASSERT(prpCue);
     RefPtrWillBeRawPtr<TextTrackCue> cue = prpCue;
 
     // TODO(93143): Add spec-compliant behavior for negative time values.
@@ -254,8 +252,7 @@ void TextTrack::addCue(PassRefPtrWillBeRawPtr<TextTrackCue> prpCue)
 
 void TextTrack::removeCue(TextTrackCue* cue, ExceptionState& exceptionState)
 {
-    if (!cue)
-        return;
+    ASSERT(cue);
 
     // 4.8.10.12.5 Text track API