Added Base64 support in TextEncoder and TextDecoder.

Source/wtf/text/TextEncodingRegistry.cpp

Index: Source/wtf/text/TextEncodingRegistry.cpp
diff --git a/Source/wtf/text/TextEncodingRegistry.cpp b/Source/wtf/text/TextEncodingRegistry.cpp
index 4dd0240043c598532f930409e545dd1a3848e671..e5dac2b971140a32c05450ff0847e38b68a4d78b 100644
--- a/Source/wtf/text/TextEncodingRegistry.cpp
+++ b/Source/wtf/text/TextEncodingRegistry.cpp
@@ -36,6 +36,7 @@
 #include "wtf/StringExtras.h"
 #include "wtf/ThreadingPrimitives.h"
 #include "wtf/text/CString.h"
+#include "wtf/text/TextCodecBase64.h"
 #include "wtf/text/TextCodecICU.h"
 #include "wtf/text/TextCodecLatin1.h"
 #include "wtf/text/TextCodecUTF16.h"
@@ -280,6 +281,9 @@ static void extendTextCodecMaps()
     TextCodecICU::registerEncodingNames(addToTextEncodingNameMap);
     TextCodecICU::registerCodecs(addToTextCodecMap);
 
+    TextCodecBase64::registerEncodingNames(addToTextEncodingNameMap);
+    TextCodecBase64::registerCodecs(addToTextCodecMap);
+
     pruneBlacklistedCodecs();
     buildQuirksSets();
 }