refactor(router): avoid circular dependency

Move const into shared file to avoid circular dependency

packages/core/test/bundling/router/bundle.golden_symbols.json

@@ -531,7 +531,7 @@
     "name": "RouteExampleModule"
   },
   {
-    "name": "RouteTitle"
+    "name": "RouteTitleKey"
   },
   {
     "name": "Router"

packages/router/src/operators/resolve_data.ts

@@ -11,9 +11,9 @@ import {EMPTY, EmptyError, from, MonoTypeOperatorFunction, Observable, of, throw
 import {catchError, concatMap, first, map, mapTo, mergeMap, takeLast, tap} from 'rxjs/operators';
 
 import {ResolveData, Route} from '../models';
-import {RouteTitle} from '../page_title_strategy';
 import {NavigationTransition} from '../router';
 import {ActivatedRouteSnapshot, inheritedParamsDataResolve, RouterStateSnapshot} from '../router_state';
+import {RouteTitleKey} from '../shared';
 import {wrapIntoObservable} from '../utils/collection';
 import {getToken} from '../utils/preactivation';
 
@@ -45,14 +45,14 @@ function runResolve(
   const config = futureARS.routeConfig;
   const resolve = futureARS._resolve;
   if (config?.title !== undefined && !hasStaticTitle(config)) {
-    resolve[RouteTitle] = config.title;
+    resolve[RouteTitleKey] = config.title;
   }
   return resolveNode(resolve, futureARS, futureRSS, moduleInjector)
       .pipe(map((resolvedData: any) => {
         futureARS._resolvedData = resolvedData;
         futureARS.data = inheritedParamsDataResolve(futureARS, paramsInheritanceStrategy).resolve;
         if (config && hasStaticTitle(config)) {
-          futureARS.data[RouteTitle] = config.title;
+          futureARS.data[RouteTitleKey] = config.title;
         }
         return null;
       }));

packages/router/src/page_title_strategy.ts

@@ -10,14 +10,7 @@ import {Injectable} from '@angular/core';
 import {Title} from '@angular/platform-browser';
 
 import {ActivatedRouteSnapshot, RouterStateSnapshot} from './router_state';
-import {PRIMARY_OUTLET} from './shared';
-
-/**
- * A private symbol used to store the value of `Route.title` inside the `Route.data` if it is a
- * static string or `Route.resolve` if anything else. This allows us to reuse the existing route
- * data/resolvers to support the title feature without new instrumentation in the `Router` pipeline.
- */
-export const RouteTitle = Symbol('RouteTitle');
+import {PRIMARY_OUTLET, RouteTitleKey} from './shared';
 
 /**
  * Provides a strategy for setting the page title after a router navigation.
@@ -64,7 +57,7 @@ export abstract class TitleStrategy {
    * `Route.title` property, which can either be a static string or a resolved value.
    */
   getResolvedTitleForRoute(snapshot: ActivatedRouteSnapshot) {
-    return snapshot.data[RouteTitle];
+    return snapshot.data[RouteTitleKey];
   }
 }
 

packages/router/src/router_state.ts

@@ -11,8 +11,7 @@ import {BehaviorSubject, Observable} from 'rxjs';
 import {map} from 'rxjs/operators';
 
 import {Data, ResolveData, Route} from './models';
-import {RouteTitle as TitleKey} from './page_title_strategy';
-import {convertToParamMap, ParamMap, Params, PRIMARY_OUTLET} from './shared';
+import {convertToParamMap, ParamMap, Params, PRIMARY_OUTLET, RouteTitleKey} from './shared';
 import {equalSegments, UrlSegment, UrlSegmentGroup, UrlTree} from './url_tree';
 import {shallowEqual, shallowEqualArrays} from './utils/collection';
 import {Tree, TreeNode} from './utils/tree';
@@ -123,7 +122,7 @@ export class ActivatedRoute {
   _queryParamMap!: Observable<ParamMap>;
 
   /** An Observable of the resolved route title */
-  readonly title: Observable<string|undefined> = this.data.pipe(map((d: Data) => d[TitleKey]));
+  readonly title: Observable<string|undefined> = this.data.pipe(map((d: Data) => d[RouteTitleKey]));
 
   /** @internal */
   constructor(
@@ -310,7 +309,7 @@ export class ActivatedRouteSnapshot {
   _queryParamMap!: ParamMap;
 
   /** The resolved route title */
-  readonly title: string|undefined = this.data?.[TitleKey];
+  readonly title: string|undefined = this.data?.[RouteTitleKey];
 
   /** @internal */
   constructor(

packages/router/src/shared.ts

@@ -17,6 +17,13 @@ import {UrlSegment, UrlSegmentGroup} from './url_tree';
  */
 export const PRIMARY_OUTLET = 'primary';
 
+/**
+ * A private symbol used to store the value of `Route.title` inside the `Route.data` if it is a
+ * static string or `Route.resolve` if anything else. This allows us to reuse the existing route
+ * data/resolvers to support the title feature without new instrumentation in the `Router` pipeline.
+ */
+export const RouteTitleKey = Symbol('RouteTitle');
+
 /**
  * A collection of matrix and query URL parameters.
  * @see `convertToParamMap()`

packages/router/test/router_state.spec.ts

@@ -8,9 +8,8 @@
 
 import {BehaviorSubject} from 'rxjs';
 
-import {RouteTitle as TitleKey} from '../src/page_title_strategy';
 import {ActivatedRoute, ActivatedRouteSnapshot, advanceActivatedRoute, equalParamsAndUrlSegments, RouterState, RouterStateSnapshot} from '../src/router_state';
-import {Params} from '../src/shared';
+import {Params, RouteTitleKey} from '../src/shared';
 import {UrlSegment} from '../src/url_tree';
 import {TreeNode} from '../src/utils/tree';
 
@@ -206,7 +205,7 @@ describe('RouterState & Snapshot', () => {
 
   describe('ActivatedRoute', () => {
     it('should get resolved route title', () => {
-      const data = {[TitleKey]: 'resolved title'};
+      const data = {[RouteTitleKey]: 'resolved title'};
       const route = createActivatedRoute('a');
       const snapshot = new (ActivatedRouteSnapshot as any)(
           <any>[], <any>null, <any>null, <any>null, data, <any>null, 'test', <any>null, <any>null,