Simplify refFromURL

Author: samtstern

packages/database/src/api/Database.ts

@@ -157,15 +157,14 @@ export class Database implements FirebaseService {
     validateUrl(apiName, 1, parsedURL);
 
     const repoInfo = parsedURL.repoInfo;
-    const expectedHost = this.repo_.originalHost;
-    if (repoInfo.host !== expectedHost) {
+    if (!repoInfo.isCustomHost() && repoInfo.host !== this.repo_.repoInfo_.host) {
       fatal(
         apiName +
           ': Host name does not match the current database: ' +
           '(found ' +
           repoInfo.host +
           ' but expected ' +
-          expectedHost +
+          this.repo_.repoInfo_.host+
           ')'
       );
     }

packages/database/src/core/Repo.ts

@@ -57,9 +57,6 @@ export class Repo {
   /** Key for uniquely identifying this repo, used in RepoManager */
   readonly key: string;
 
-  /** Record of the original host, which does not change even if useEmulator mutates the repo */
-  readonly originalHost: string;
-
   dataUpdateCount = 0;
   private infoSyncTree_: SyncTree;
   private serverSyncTree_: SyncTree;
@@ -93,7 +90,6 @@ export class Repo {
   ) {
     // This key is intentionally not updated if RepoInfo is later changed or replaced
     this.key = this.repoInfo_.toURLString();
-    this.originalHost = this.repoInfo_.host;
   }
 
   start(): void {

packages/database/test/database.test.ts

@@ -229,8 +229,8 @@ describe('Database Tests', () => {
   });
 
   it('ref() validates project', () => {
-    const db1 = defaultApp.database('http://bar.foo.com');
-    const db2 = defaultApp.database('http://foo.bar.com');
+    const db1 = defaultApp.database('http://bar.firebaseio.com');
+    const db2 = defaultApp.database('http://foo.firebaseio.com');
 
     const ref1 = db1.ref('child');