addressed comments

src/frames.ts

@@ -309,8 +309,11 @@ export class Frame {
 
   async goto(url: string, options?: GotoOptions): Promise<network.Response | null> {
     let referer = (this._page._state.extraHTTPHeaders || {})['referer'];
-    if (options && options.referer !== undefined)
+    if (options && options.referer !== undefined) {
+      if (referer !== undefined && referer !== options.referer)
+        throw new Error('"referer" is already specified as extra HTTP header');
       referer = options.referer;
+    }
     const watcher = new LifecycleWatcher(this, options, false /* supportUrlMatch */);
 
     let navigateResult: GotoResult;

src/page.ts

@@ -171,18 +171,6 @@ export class Page extends platform.EventEmitter {
     this.emit(Events.Page.FileChooser, fileChooser);
   }
 
-  _validateNavigationReferrer(referrer: string | undefined) {
-    if (!referrer)
-      return;
-    if (!this._state.extraHTTPHeaders)
-      return;
-    const header = this._state.extraHTTPHeaders['referer'];
-    if (!header)
-      return;
-    if (header !== referrer)
-      throw new Error('"referer" is already specified as extra HTTP header');
-  }
-
   browserContext(): BrowserContext {
     return this._browserContext;
   }

src/webkit/wkPage.ts

@@ -223,7 +223,6 @@ export class WKPage implements PageDelegate {
   }
 
   async navigateFrame(frame: frames.Frame, url: string, referrer: string | undefined): Promise<frames.GotoResult> {
-    this._page._validateNavigationReferrer(referrer);
     if (this._pageProxySession.isDisposed())
       throw new Error('Target closed');
     const pageProxyId = this._pageProxySession.sessionId;

test/navigation.spec.js

@@ -322,26 +322,13 @@ module.exports.describe = function({testRunner, expect, playwright, FFOX, CHROMI
       expect(request2.headers['referer']).toBe(server.PREFIX + '/grid.html');
       expect(page.url()).toBe(server.PREFIX + '/grid.html');
     });
-    it('should use referer option when setExtraHTTPHeaders provides referer', async({page, server}) => {
+    it('should reject referer option when setExtraHTTPHeaders provides referer', async({page, server}) => {
       await page.setExtraHTTPHeaders({ 'referer': 'http://microsoft.com/' });
-      try {
+      let error;
-        const [request1, request2] = await Promise.all([
+      await page.goto(server.PREFIX + '/grid.html', {
-          server.waitForRequest('/grid.html'),
+        referer: 'http://google.com/',
-          server.waitForRequest('/digits/1.png'),
+      }).catch(e => error = e);
-          page.goto(server.PREFIX + '/grid.html', {
+      expect(error.message).toBe('"referer" is already specified as extra HTTP header');
-            referer: 'http://google.com/',
-          }),
-        ]);
-        expect(request1.headers['referer']).toBe('http://google.com/');
-        // Make sure subresources use referer specified by setExtraHTTPHeaders.
-        expect(request2.headers['referer']).toBe('http://microsoft.com/');
-        expect(page.url()).toBe(server.PREFIX + '/grid.html');
-      } catch (error) {
-        if (FFOX || WEBKIT)
-          expect(error.message).toBe('"referer" is already specified as extra HTTP header');
-        else
-          throw error;
-      }
     });
     it('should override referrer-policy', async({page, server}) => {
       server.setRoute('/grid.html', (req, res) => {