Drop [LegacyInterfaceTypeChecking] where trivial in Web Audio

third_party/WebKit/Source/modules/webaudio/AudioBuffer.cpp

Index: third_party/WebKit/Source/modules/webaudio/AudioBuffer.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioBuffer.cpp b/third_party/WebKit/Source/modules/webaudio/AudioBuffer.cpp
index d7c888848d0e54971342da1dda9e783cc74c0342..33879451908853f37c82b30575efd0970d8be752 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioBuffer.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioBuffer.cpp
@@ -208,15 +208,6 @@ void AudioBuffer::copyFromChannel(DOMFloat32Array* destination, long channelNumb
 
 void AudioBuffer::copyFromChannel(DOMFloat32Array* destination, long channelNumber, unsigned long startInChannel, ExceptionState& exceptionState)
 {
-    if (!destination) {
-        exceptionState.throwDOMException(
-            TypeMismatchError,
-            ExceptionMessages::argumentNullOrIncorrectType(
-                1,
-                "Float32Array"));
-        return;
-    }
-
     if (channelNumber < 0 || channelNumber >= static_cast<long>(m_channels.size())) {
         exceptionState.throwDOMException(
             IndexSizeError,
@@ -265,15 +256,6 @@ void AudioBuffer::copyToChannel(DOMFloat32Array* source, long channelNumber, Exc
 
 void AudioBuffer::copyToChannel(DOMFloat32Array* source, long channelNumber, unsigned long startInChannel, ExceptionState& exceptionState)
 {
-    if (!source) {
-        exceptionState.throwDOMException(
-            TypeMismatchError,
-            ExceptionMessages::argumentNullOrIncorrectType(
-                1,
-                "Float32Array"));
-        return;
-    }
-
     if (channelNumber < 0 || channelNumber >= static_cast<long>(m_channels.size())) {
         exceptionState.throwDOMException(
             IndexSizeError,