Use IDL argument default values in modules/encoding/

Source/modules/encoding/TextEncoder.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 23 matching lines @@
 
 #include "bindings/v8/Dictionary.h"
 #include "bindings/v8/ExceptionState.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/TextEncodingRegistry.h"
 
 namespace WebCore {
 
 TextEncoder* TextEncoder::create(const String& utfLabel, ExceptionState& exceptionState)
 {
-    const String& encodingLabel = utfLabel.isNull() ? String("utf-8") : utfLabel;
-
-    WTF::TextEncoding encoding(encodingLabel);
+    WTF::TextEncoding encoding(utfLabel);
     if (!encoding.isValid()) {
-        exceptionState.throwTypeError("The encoding label provided ('" + encodingLabel + "') is invalid.");
+        exceptionState.throwTypeError("The encoding label provided ('" + utfLabel + "') is invalid.");
         return 0;
     }
 
     String name(encoding.name());
     if (name != "UTF-8" && name != "UTF-16LE" && name != "UTF-16BE") {
-        exceptionState.throwTypeError("The encoding provided ('" + encodingLabel + "') is not one of 'utf-8', 'utf-16', or 'utf-16be'.");
+        exceptionState.throwTypeError("The encoding provided ('" + utfLabel + "') is not one of 'utf-8', 'utf-16', or 'utf-16be'.");
         return 0;
     }
 
     return new TextEncoder(encoding);
 }
 
 TextEncoder::TextEncoder(const WTF::TextEncoding& encoding)
     : m_encoding(encoding)
     , m_codec(newTextCodec(encoding))
 {
@@ skipping 12 matching lines @@
 
 PassRefPtr<Uint8Array> TextEncoder::encode(const String& input, const Dictionary& options)
 {
     bool stream = false;
     options.get("stream", stream);
 
     // FIXME: Not flushing is not supported by TextCodec for encode; add it or
     // handle split surrogates here.
 
     CString result;
-    if (!input.isNull()) {
-        if (input.is8Bit())
-            result = m_codec->encode(input.characters8(), input.length(), WTF::QuestionMarksForUnencodables);
-        else
-            result = m_codec->encode(input.characters16(), input.length(), WTF::QuestionMarksForUnencodables);
-    }
+    if (input.is8Bit())
+        result = m_codec->encode(input.characters8(), input.length(), WTF::QuestionMarksForUnencodables);
+    else
+        result = m_codec->encode(input.characters16(), input.length(), WTF::QuestionMarksForUnencodables);
 
     const char* buffer = result.data();
     const unsigned char* unsignedBuffer = reinterpret_cast<const unsigned char*>(buffer);
 
     return Uint8Array::create(unsignedBuffer, result.length());
 }
 
 } // namespace WebCore