Bug 172000 [Wizards] WizardNewFileCreationPage should support overwriting existing resources
In the WizardNewFileCreationPage, there should be a method to set allowExistingResources flag for ResourceAndContainerGroup member. It is useful when both "create" and "renew/overwrite" operations are meaningful for a wizard.
bundles/org.eclipse.ui.ide/extensions/org/eclipse/ui/dialogs/WizardNewFileCreationPage.java
}
		validatePage();
		
		setErrorMessage(null);
		setMessage(null);
		setControl(topLevel);
	}
	/**
	 * Creates a file resource given the file handle and contents.
	 * 
	 * @param fileHandle
	 *            the file handle to create a file resource with
	 * @param contents
	 *            the initial contents of the new file resource, or
	 *            <code>null</code> if none (equivalent to an empty stream)
	 * @param monitor
	 *            the progress monitor to show visual progress with
	 * @exception CoreException
	 *                if the operation fails
	 * @exception OperationCanceledException
	 *                if the operation is canceled
	 * 
	 * @deprecated As of 3.3, use or override {@link #createNewFile()} which
	 *             uses the undoable operation support. To supply customized
	 *             file content for a subclass, use
	 *             {@link #getInitialContents()}.
	 */
	protected void createFile(IFile fileHandle, InputStream contents,
			IProgressMonitor monitor) throws CoreException {
		if (contents == null) {