Bug 187796 [KeyBindings] IBindingService cannot return best active bindings for a ParameterizedCommand
IBindingService only supports getBestActiveBindingFor(final String commandId) ... there must be an equivalent method for ParameterizedCommands PW
bundles/org.eclipse.jface/src/org/eclipse/jface/bindings/BindingManager.java
* 
	 * @param trigger
	 *            The sequence which should be the prefix for some binding;
	 *            should not be <code>null</code>.
	 * @return <code>true</code> if the trigger can be found in the active
	 *         bindings; <code>false</code> otherwise.
	 */
	public final boolean isPartialMatch(final TriggerSequence trigger) {
		return (getPrefixTable().get(trigger) != null);
	}
	/**
	 * <p>
	 * Returns whether the given trigger sequence is a perfect match for the
	 * given sequence.
	 * </p>
	 * <p>
	 * This method completes in <code>O(1)</code>. If the bindings aren't
	 * currently computed, then this completes in <code>O(n)</code>, where
	 * <code>n</code> is the number of bindings.
	 * </p>
	 * 
	 * @param trigger
	 *            The sequence which should match exactly; should not be
	 *            <code>null</code>.
	 * @return <code>true</code> if the trigger can be found in the active
	 *         bindings; <code>false</code> otherwise.
	 */
	public final boolean isPerfectMatch(final TriggerSequence trigger) {
		return getActiveBindings().containsKey(trigger);
	}