FormData should not drop ignorable code points.

third_party/WebKit/Source/wtf/text/TextCodecICU.cpp

 /*
  * Copyright (C) 2004, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov <ap@nypop.com>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 406 matching lines @@
         *err = U_ZERO_ERROR;
 
         UnencodableReplacementArray entity;
         int entityLen = TextCodec::getUnencodableReplacement(codePoint, handling, entity);
         ucnv_cbFromUWriteBytes(fromUArgs, entity, entityLen, 0, err);
     } else {
         UCNV_FROM_U_CALLBACK_ESCAPE(context, fromUArgs, codeUnits, length, codePoint, reason, err);
     }
 }
 
+static void numericEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
+    UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
+{
+    formatEscapedEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err, EntitiesForUnencodables);
+}
+
 // Invalid character handler when writing escaped entities in CSS encoding for
 // unrepresentable characters. See the declaration of TextCodec::encode for more.
 static void cssEscapedEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
     UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
 {
     formatEscapedEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err, CSSEncodedEntitiesForUnencodables);
 }
 
 // Invalid character handler when writing escaped entities in HTML/XML encoding for
 // unrepresentable characters. See the declaration of TextCodec::encode for more.
 static void urlEscapedEntityCallback(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
     UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
 {
     formatEscapedEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err, URLEncodedEntitiesForUnencodables);
 }
 
 #if defined(USING_SYSTEM_ICU)
 // Substitutes special GBK characters, escaping all other unassigned entities.
 static void gbkCallbackEscape(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
     UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
 {
     UChar outChar;
     if (reason == UCNV_UNASSIGNED && (outChar = fallbackForGBK(codePoint))) {
         const UChar* source = &outChar;
         *err = U_ZERO_ERROR;
         ucnv_cbFromUWriteUChars(fromUArgs, &source, source + 1, 0, err);
         return;
     }
-    UCNV_FROM_U_CALLBACK_ESCAPE(context, fromUArgs, codeUnits, length, codePoint, reason, err);
+    numericEntityCallback(context, fromUArgs, codeUnits, length, codePoint, reason, err);
 }
 
 // Combines both gbkCssEscapedEntityCallback and GBK character substitution.
 static void gbkCssEscapedEntityCallack(const void* context, UConverterFromUnicodeArgs* fromUArgs, const UChar* codeUnits, int32_t length,
     UChar32 codePoint, UConverterCallbackReason reason, UErrorCode* err)
 {
     if (reason == UCNV_UNASSIGNED) {
         if (UChar outChar = fallbackForGBK(codePoint)) {
             const UChar* source = &outChar;
             *err = U_ZERO_ERROR;
@@ skipping 74 matching lines @@
     case QuestionMarksForUnencodables:
         ucnv_setSubstChars(m_converterICU, "?", 1, &err);
 #if !defined(USING_SYSTEM_ICU)
         ucnv_setFromUCallBack(m_converterICU, UCNV_FROM_U_CALLBACK_SUBSTITUTE, 0, 0, 0, &err);
 #else
         ucnv_setFromUCallBack(m_converterICU, m_needsGBKFallbacks ? gbkCallbackSubstitute : UCNV_FROM_U_CALLBACK_SUBSTITUTE, 0, 0, 0, &err);
 #endif
         break;
     case EntitiesForUnencodables:
 #if !defined(USING_SYSTEM_ICU)
-        ucnv_setFromUCallBack(m_converterICU, UCNV_FROM_U_CALLBACK_ESCAPE, UCNV_ESCAPE_XML_DEC, 0, 0, &err);
+        ucnv_setFromUCallBack(m_converterICU, numericEntityCallback, 0, 0, 0, &err);
 #else
-        ucnv_setFromUCallBack(m_converterICU, m_needsGBKFallbacks ? gbkCallbackEscape : UCNV_FROM_U_CALLBACK_ESCAPE, UCNV_ESCAPE_XML_DEC, 0, 0, &err);
+        ucnv_setFromUCallBack(m_converterICU, m_needsGBKFallbacks ? gbkCallbackEscape : numericEntityCallback, 0, 0, 0, &err);
 #endif
         break;
     case URLEncodedEntitiesForUnencodables:
 #if !defined(USING_SYSTEM_ICU)
         ucnv_setFromUCallBack(m_converterICU, urlEscapedEntityCallback, 0, 0, 0, &err);
 #else
         ucnv_setFromUCallBack(m_converterICU, m_needsGBKFallbacks ? gbkUrlEscapedEntityCallack : urlEscapedEntityCallback, 0, 0, 0, &err);
 #endif
         break;
     case CSSEncodedEntitiesForUnencodables:
@@ skipping 45 matching lines @@
 {
     return encodeCommon(characters, length, handling);
 }
 
 CString TextCodecICU::encode(const LChar* characters, size_t length, UnencodableHandling handling)
 {
     return encodeCommon(characters, length, handling);
 }
 
 } // namespace WTF