Bug 174555 [DataBinding] Run validation on binding construction
When a binding is created the assumption is that the UI is synchronized with the model. This means that the UI should reflect the state of the model's validity as well. In order to ensure that the UI reflects the model's validity the consumer needs to force a copy to model on instantiation of every binding. We need to remove this requirement.
tests/org.eclipse.jface.tests.databinding/src/org/eclipse/jface/tests/internal/databinding/internal/beans/JavaBeanObservableValueTest.java
public void testGetPropertyDescriptor() throws Exception {
    	assertEquals(propertyDescriptor, observableValue.getPropertyDescriptor());
	}
    
    public void testRegistersListenerAfterFirstListenerIsAdded() throws Exception {
		assertFalse(bean.changeSupport.hasListeners(propertyName));
		observableValue.addValueChangeListener(new ValueChangeListener());
		assertTrue(bean.changeSupport.hasListeners(propertyName));
	}
    
    public void testRemovesListenerAfterLastListenerIsRemoved() throws Exception {
    	ValueChangeListener listener = new ValueChangeListener();
		observableValue.addValueChangeListener(listener);
		
		assertTrue(bean.changeSupport.hasListeners(propertyName));
		observableValue.removeValueChangeListener(listener);
		assertFalse(bean.changeSupport.hasListeners(propertyName));
	}
    
    public void testFiresValueChangeEvents() throws Exception {
    	ValueChangeListener listener = new ValueChangeListener();
    	observableValue.addValueChangeListener(listener);
    	
    	assertEquals(0, listener.count);
    	bean.setValue(bean.getValue() + bean.getValue());
    	assertEquals(1, listener.count);
	}
    
    static class ValueChangeListener implements IValueChangeListener {