feat(platform-server): Implement PlatformLocation for platformServer() (#14405)

This gives server-side apps a current URL including hash, but doesn't implement a state stack,
so back-and-forward navigation isn't possible.

PR Close #14405

modules/@angular/platform-server/test/integration_spec.ts

@@ -7,6 +7,7 @@
  */
 
 import {Component, NgModule, destroyPlatform} from '@angular/core';
+import {PlatformLocation} from '@angular/common';
 import {async} from '@angular/core/testing';
 import {getDOM} from '@angular/platform-browser/src/dom/dom_adapter';
 import {ServerModule, platformDynamicServer} from '@angular/platform-server';
@@ -31,7 +32,7 @@ class ExampleModule {
 export function main() {
   if (getDOM().supportsDOMEvents()) return;  // NODE only
 
-  describe('platform-server integration', () => {
+  fdescribe('platform-server integration', () => {
 
     beforeEach(() => destroyPlatform());
     afterEach(() => destroyPlatform());
@@ -42,5 +43,38 @@ export function main() {
            expect(getDOM().getText(body)).toEqual('Works!');
          });
        }));
+    
+    describe('PlatformLocation', () => {
+      it('is injectable', () => {
+        const body = writeBody('<app></app>');
+        platformDynamicServer().bootstrapModule(ExampleModule).then(appRef => {
+          const location: PlatformLocation = appRef.injector.get(PlatformLocation);
+          expect(location.pathname).toBe('/');
+        });
+      });
+      it('pushState causes the URL to update', () => {
+        const body = writeBody('<app></app>');
+        platformDynamicServer().bootstrapModule(ExampleModule).then(appRef => {
+          const location: PlatformLocation = appRef.injector.get(PlatformLocation);
+          location.pushState(null, 'Test', '/foo#bar');
+          expect(location.pathname).toBe('/foo');
+          expect(location.hash).toBe('#bar');
+        });
+      });
+      it('allows subscription to the hash state', done => {
+        const body = writeBody('<app></app>');
+        platformDynamicServer().bootstrapModule(ExampleModule).then(appRef => {
+          const location: PlatformLocation = appRef.injector.get(PlatformLocation);
+          expect(location.pathname).toBe('/');
+          location.onHashChange((e: any) => {
+            expect(e.type).toBe('hashchange');
+            expect(e.oldUrl).toBe('/');
+            expect(e.newUrl).toBe('/foo#bar');
+            done();
+          });
+          location.pushState(null, 'Test', '/foo#bar');
+        });
+      });
+    });
   });
 }