Escape all of invalid values in console messages for INPUT elements.

Source/platform/JSONValues.cpp

Index: Source/platform/JSONValues.cpp
diff --git a/Source/platform/JSONValues.cpp b/Source/platform/JSONValues.cpp
index a0e4e733778b57767e9cea0312bc4b19490548fa..a318733a3235263f5dceb818af2b7e45f7f81eed 100644
--- a/Source/platform/JSONValues.cpp
+++ b/Source/platform/JSONValues.cpp
@@ -88,6 +88,13 @@ void writeIndent(int depth, StringBuilder* output)
 
 } // anonymous namespace
 
+String JSONValue::quoteString(const String& input)
+{
+    StringBuilder builder;
+    doubleQuoteString(input, &builder);
+    return builder.toString();
+}
+
 bool JSONValue::asBoolean(bool*) const
 {
     return false;