More work towards supporting multiple global objects. Native C++ code
now get a GlobalObject& and don't have to ask the Interpreter for it.
I've added macros for declaring and defining native callbacks since
this was pretty tedious and this makes it easier next time we want to
change any of these signatures.
This patch adds very basic XMLHttpRequest support to LibWeb. Here's an
example that currently works:
var callback = function() { alert(this.responseText); }
var xhr = new XMLHttpRequest();
xhr.addEventListener("load", callback);
xhr.open("GET", "http://serenityos.org/~kling/test/example.txt");
xhr.send();
There are many limitations and bugs, but it's pretty dang awesome that
we have XHR. :^)
LibWeb now creates a WindowObject which inherits from GlobalObject.
Allocation of the global object is moved out of the Interpreter ctor
to allow for specialized construction.
The existing Window interfaces are moved to WindowObject with their
implementation code in the new Window class.
