Deflake WebAuthJavascriptClientBrowserTest.CreatePublicKeyCredentialWithAbortSetAfterCreate

Fixed: 1166254
Change-Id: I4bfd0c178757d7b24959180b9db083d545607b68
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628046
Auto-Submit: Adam Langley <agl@chromium.org>
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#843324}

content/browser/webauth/webauth_browsertest.cc

@@ -994,7 +994,17 @@ IN_PROC_BROWSER_TEST_F(WebAuthJavascriptClientBrowserTest,
 // signal's aborted flag set after sending request, we get an AbortError.
 IN_PROC_BROWSER_TEST_F(WebAuthJavascriptClientBrowserTest,
                        CreatePublicKeyCredentialWithAbortSetAfterCreate) {
-  InjectVirtualFidoDeviceFactory();
+  // This test sends the abort signal after making the WebAuthn call. However,
+  // the WebAuthn call could complete before the abort signal is sent, leading
+  // to a flakey test. Thus the |simulate_press_callback| is installed and
+  // always returns false, to ensure that the VirtualFidoDevice stalls the
+  // WebAuthn call and the abort signal will happen in time.
+  device::test::VirtualFidoDeviceFactory* virtual_device_factory =
+      InjectVirtualFidoDeviceFactory();
+  virtual_device_factory->mutable_state()->simulate_press_callback =
+      base::BindRepeating(
+          [](device::VirtualFidoDevice*) -> bool { return false; });
+
   CreateParameters parameters;
   parameters.signal = "authAbortSignal";
   std::string result;