Remove the Document.charset setter (making it readonly)

Source/core/frame/UseCounter.cpp

Index: Source/core/frame/UseCounter.cpp
diff --git a/Source/core/frame/UseCounter.cpp b/Source/core/frame/UseCounter.cpp
index c870b002a983314c39ca3b81f51236891aa39459..8d81f4fd0857a6cdacb7c4ad07e3154127c92903 100644
--- a/Source/core/frame/UseCounter.cpp
+++ b/Source/core/frame/UseCounter.cpp
@@ -833,9 +833,6 @@ String UseCounter::deprecationMessage(Feature feature)
     case GetMatchedCSSRules:
         return "'getMatchedCSSRules()' is deprecated. For more help, check https://code.google.com/p/chromium/issues/detail?id=437569#c2";
 
-    case DocumentSetCharset:
-        return "Setting 'Document.charset' is deprecated. Please use '<meta charset=\"UTF-8\">' instead.";
-
     case PrefixedImageSmoothingEnabled:
         return replacedBy("CanvasRenderingContext2D.webkitImageSmoothingEnabled", "CanvasRenderingContext2D.imageSmoothingEnabled");