Bug 49117 [Plan Item] Workbench needs hooks for new welcome support
M6 We need to provide an extension point and some interfaces to allow for a primary feature to declare a welcome page. This extension point will be tied the new IProduct being defined by the Core team and needs to have 3 states 1) Fill whole screen 2) Collapsed on the right when the user selects something and starts working 3) Disables when it is no longer of any use
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/IDEWorkbenchAdvisor.java
String perspectiveId = null;
		if (index >=0 && welcomePerspectiveInfos != null && index < welcomePerspectiveInfos.size()) {
			perspectiveId = ((AboutInfo) welcomePerspectiveInfos.get(index)).getWelcomePerspectiveId();
		}
		if (perspectiveId == null) {
			perspectiveId = IDE.RESOURCE_PERSPECTIVE_ID;
		}
		return perspectiveId;
	}
	/*
	 * Open the welcome editor for the primary feature and
	 * for any newly installed features.
	 */
	private void openWelcomeEditors() throws WorkbenchException {
		IWorkbenchWindow window = configurer.getWorkbench().getActiveWorkbenchWindow();
		if (window == null) {
			if (configurer.getWorkbench().getWorkbenchWindowCount() > 0) {
				window = configurer.getWorkbench().getWorkbenchWindows()[0];
			} else {
				return;
			}
		}
		if (IDEWorkbenchPlugin.getDefault().getPreferenceStore().getBoolean(IDEInternalPreferences.WELCOME_DIALOG)) {
			
			AboutInfo primaryInfo = IDEWorkbenchPlugin.getDefault().getPrimaryInfo();
			if (primaryInfo == null) {
				return;
			}
			URL url = primaryInfo.getWelcomePageURL();
			if (url == null) {