Add ByteString support to IDL bindings

Source/bindings/v8/V8Binding.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
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  *     * Redistributions in binary form must reproduce the above
@@ skipping 474 matching lines @@
     NonThrowableExceptionState exceptionState;
     return toUInt64(value, NormalConversion, exceptionState);
 }
 
 float toFloat(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
 {
     TONATIVE_DEFAULT_EXCEPTIONSTATE(v8::Local<v8::Number>, numberObject, value->ToNumber(), exceptionState, 0);
     return numberObject->NumberValue();
 }
 
+String toByteString(v8::Handle<v8::Value> value, ExceptionState& exceptionState)
+{
+    String string = toCoreString(value.As<v8::String>());

[jsbell, 2014/05/30 21:53:28]

Yeah, this As<v8::String> is bogus if it's not a string. I'll dig further.

[Nils Barth (inactive), 2014/06/02 03:20:16]

Should it be ToString() instead then?
(JS values are all stringifable.)
Anyway, that's what the spec says, right?:
http://heycam.github.io/webidl/#es-ByteString

In any case, could you link to the spec here (per above URL),
and quote line-by-line so the spec <-> code correspondence is explicit?
(V. useful if the spec changes!)

E.g. (with whatever the correct code is):
// 1. Let x be ToString(V).
String string = value.ToString();
// 2. If the value of any element of x is greater than 255, then throw a
TypeError.
if (!...)

[jsbell, 2014/06/03 23:22:36]

Yeah; handling should be identical to js->DOMString, except for the extra
throwing case.

That does mean the ToString needs to handle the conversion itself throwing. Was
afraid of the macros, but I've got that sorted now.

+    if (!string.containsOnlyLatin1()) {
+        exceptionState.throwTypeError("Value is not a valid ByteString.");
+        return String();
+    }
+    return string;
+}
+
 PassRefPtrWillBeRawPtr<XPathNSResolver> toXPathNSResolver(v8::Handle<v8::Value> value, v8::Isolate* isolate)
 {
     RefPtrWillBeRawPtr<XPathNSResolver> resolver = nullptr;
     if (V8XPathNSResolver::hasInstance(value, isolate))
         resolver = V8XPathNSResolver::toNative(v8::Handle<v8::Object>::Cast(value));
     else if (value->IsObject())
         resolver = V8CustomXPathNSResolver::create(value->ToObject(), isolate);
     return resolver;
 }
 
@@ skipping 285 matching lines @@
 PassRefPtr<TraceEvent::ConvertableToTraceFormat> devToolsTraceEventData(ExecutionContext* context, v8::Handle<v8::Function> function, v8::Isolate* isolate)
 {
     int scriptId = 0;
     String resourceName;
     int lineNumber = 1;
     GetDevToolsFunctionInfo(function, isolate, scriptId, resourceName, lineNumber);
     return InspectorFunctionCallEvent::data(context, scriptId, resourceName, lineNumber);
 }
 
 } // namespace WebCore