IDL: make optional arguments (without default) explicit sometimes

Source/modules/mediastream/RTCDTMFSender.cpp

Index: Source/modules/mediastream/RTCDTMFSender.cpp
diff --git a/Source/modules/mediastream/RTCDTMFSender.cpp b/Source/modules/mediastream/RTCDTMFSender.cpp
index e59854324ed1711c90261d3b9472c7b14be41c5a..1c7e56305d18bf3018fba95b2fefde0991922ec2 100644
--- a/Source/modules/mediastream/RTCDTMFSender.cpp
+++ b/Source/modules/mediastream/RTCDTMFSender.cpp
@@ -89,16 +89,6 @@ String RTCDTMFSender::toneBuffer() const
     return m_handler->currentToneBuffer();
 }
 
-void RTCDTMFSender::insertDTMF(const String& tones, ExceptionState& exceptionState)
-{
-    insertDTMF(tones, defaultToneDurationMs, defaultInterToneGapMs, exceptionState);
-}
-
-void RTCDTMFSender::insertDTMF(const String& tones, long duration, ExceptionState& exceptionState)
-{
-    insertDTMF(tones, duration, defaultInterToneGapMs, exceptionState);
-}
-
 void RTCDTMFSender::insertDTMF(const String& tones, long duration, long interToneGap, ExceptionState& exceptionState)
 {
     if (!canInsertDTMF()) {