Bug 123496 [IDE] Use operation validation API for IDE actions
We should use the Resources/Core operation validation API in the IDE actions for manipulating resources.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/ide/IDE.java
if (desc != null)
                    return desc;
            }
        } catch (CoreException e) {
            
        }
        
		IContentType contentType = null;
		if (determineContentType)
			contentType = getContentType(file);    
        
        return editorReg.getDefaultEditor(file.getName(), contentType);
    }
    /**
     * Extracts and returns the <code>IResource</code>s in the given
     * selection or the resource objects they adapts to.
     * 
     * @param originalSelection the original selection, possibly empty
     * @return list of resources (element type: <code>IResource</code>), 
     *    possibly empty
     */
    public static List computeSelectedResources(
            IStructuredSelection originalSelection) {
        List resources = null;
        for (Iterator e = originalSelection.iterator(); e.hasNext();) {
            Object next = e.next();
            Object resource = null;
            if (next instanceof IResource) {
                resource = next;
            } else if (next instanceof IAdaptable) {