message: docs(router): Further document rawUrlTree
  Further document the rawUrlTree and how it's used internally in the Router.
  PR Close
diff: @@ -369,6 +369,21 @@ export class Router {
  * rawUrlTree to be a combination of the urlAfterRedirects (again, this might only apply to part
  * of the initial url) and the rawUrl of the transition (which was the original navigation url in
  * its full form).
  + *
  + * Note that this is _only_ here to support `UrlHandlingStrategy.extract` and
  + * `UrlHandlingStrategy.shouldProcessUrl`. If those didn't exist, we could get by with
  + * `currentUrlTree` alone. If a new Router were to be provided (i.e. one that works with the
  + * browser navigation API), we should think about whether this complexity should be carried over.
  + *
  + * - extract: `rawUrlTree` is needed because `extract` may only return part
  + * of the navigation URL. Thus, `currentUrlTree` may only represent _part_ of the browser URL.
  + * When a navigation gets cancelled and we need to reset the URL or a new navigation occurs, we
  + * need to know the _whole_ browser URL, not just the part handled by UrlHandlingStrategy.
  + * - shouldProcessUrl: When this returns `false`, the router just ignores the navigation but still
  + * updates the `rawUrlTree` with the assumption that the navigation was caused by the location
  + * change listener due to a URL update by the AngularJS router. In this case, we still need to
  + * know what the browser's URL is for future navigations.
  + *
  */
  private rawUrlTree: UrlTree;
  /**
  