Bug 126414 [Commands] handlers: Provide help context ids
For commands and handlers to replace actions, they need to be capable of providing help context identifiers. For an example, see OpenResourceHandler in org.eclipse.ui.ide. This help context id will need to be definable through XML and through code.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/CommandManager.java
return categories;
	}
	/**
	 * Returns the set of identifiers for those category that are defined.
	 * 
	 * @return The set of defined category identifiers; this value may be empty,
	 *         but it is never <code>null</code>.
	 */
	public final Set getDefinedCategoryIds() {
		return Collections.unmodifiableSet(definedCategoryIds);
	}
	/**
	 * Returns the set of identifiers for those commands that are defined.
	 * 
	 * @return The set of defined command identifiers; this value may be empty,
	 *         but it is never <code>null</code>.
	 */
	public final Set getDefinedCommandIds() {
		return getDefinedHandleObjectIds();
	}
	/**
	 * Returns the commands that are defined.
	 * 
	 * @return The defined commands; this value may be empty, but it is never
	 *         <code>null</code>.
	 * @since 3.2
	 */
	public final Command[] getDefinedCommands() {
		return (Command[]) definedHandleObjects
				.toArray(new Command[definedHandleObjects.size()]);