Bug 167450 [DataBinding] Get rid of bind support factory magic
I finally realized that we don't need that other magic factory. I'll move fillBindSpecDefaults() and the methods it calls (createConverter, createValidator etc) to a new class DefaultBindSpec. Clients who want default validators and converters created for them just create a DefaultBindSpec as opposed to a (rather empty) BindSpec. I will also move the early type checking into DefaultBindSpec to make it optional as well.
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/BindSupportFactory.java
/**
	 * Creates a converter for the given from and to types and model
	 * description. Either toType or modelDescription can be null, but not both.
	 * The returned converter (if not null) should convert values of type
	 * fromType to values of type toType (in the case that toType is given), and
	 * (in the case that modelDescription is given) convert to the type expected
	 * by updatable objects created from the given model description.
	 * 
	 * @param fromType
	 *            The type to convert from
	 * @param toType
	 *            The type to convert to, or <code>null</code> if not known
	 * @return a converter, or <code>null</code> if this factory cannot create
	 *         a converter for the given arguments.
	 */
	public IConverter createConverter(Object fromType, Object toType) {
		return null;
	}
	/**
	 * @param fromType
	 * @param toType
	 * @return whether fromType is assignable to toType, or <code>null</code>
	 *         if this factory cannot determine assignability between the given
	 *         types
	 */
	public Boolean isAssignableFromTo(Object fromType, Object toType) {
		return null;
	}
}