Remove the Document.charset setter (making it readonly)

Source/core/html/parser/TextResourceDecoder.cpp

Index: Source/core/html/parser/TextResourceDecoder.cpp
diff --git a/Source/core/html/parser/TextResourceDecoder.cpp b/Source/core/html/parser/TextResourceDecoder.cpp
index d30ab51c79fc565d5176ba5868817e2909b0a7f4..7c483538ae2e3bf7f81ee0808da03883f4b568d9 100644
--- a/Source/core/html/parser/TextResourceDecoder.cpp
+++ b/Source/core/html/parser/TextResourceDecoder.cpp
@@ -330,7 +330,7 @@ bool TextResourceDecoder::checkForXMLCharset(const char* data, size_t len, bool&
 
 void TextResourceDecoder::checkForMetaCharset(const char* data, size_t length)
 {
-    if (m_source == UserChosenEncoding || m_source == EncodingFromHTTPHeader || m_source == AutoDetectedEncoding) {
+    if (m_source == EncodingFromHTTPHeader || m_source == AutoDetectedEncoding) {
         m_checkedForMetaCharset = true;
         return;
     }