Add clickDialogButton methods for FedCM

This builds on commit 7ad44ee

The specification for clickdialogbutton is here:
https://fedidcg.github.io/FedCM/#webdriver-clickdialogbutton

The version that takes an index is specified here:
w3c-fedid/FedCM#610

Bug #12088

java/src/org/openqa/selenium/federatedcredentialmanagement/FederatedCredentialManagementDialog.java

@@ -29,6 +29,11 @@ public interface FederatedCredentialManagementDialog {
   String DIALOG_TYPE_ACCOUNT_LIST = "AccountChooser";
   String DIALOG_TYPE_AUTO_REAUTH = "AutoReauthn";
 
+  String BUTTON_CONFIRM_IDP_LOGIN_CONTINUE = "ConfirmIdpLoginContinue";
+  // The following buttons need an account index.
+  String BUTTON_TERMS_OF_SERVICE = "TermsOfService";
+  String BUTTON_PRIVACY_POLICY = "PrivacyPolicy";
+
   /** Closes the dialog as if the user had clicked X. */
   void cancelDialog();
 
@@ -58,4 +63,19 @@ public interface FederatedCredentialManagementDialog {
    * <p>If this is an auto reauth dialog, returns the single account that is being signed in.
    */
   List<FederatedCredentialManagementAccount> getAccounts();
+
+  /**
+   * Clicks a button on the dialog.
+   *
+   * @param button The button to click.
+   */
+  void clickButton(String button);
+
+  /**
+   * Clicks a button on the dialog that requires an account index.
+   *
+   * @param button The button to click.
+   * @param index The account index, if needed by the specified button.
+   */
+  void clickButton(String button, int index);
 }

java/src/org/openqa/selenium/remote/FedCmDialogImpl.java

@@ -70,4 +70,15 @@ public List<FederatedCredentialManagementAccount> getAccounts() {
     }
     return accounts;
   }
+
+  @Override
+  public void clickButton(String button) {
+    executeMethod.execute(DriverCommand.CLICK_DIALOG, Map.of("dialogButton", button));
+  }
+
+  @Override
+  public void clickButton(String button, int index) {
+    executeMethod.execute(DriverCommand.CLICK_DIALOG,
+        Map.of("dialogButton", button, "index", index));
+  }
 }

java/test/org/openqa/selenium/federatedcredentialmanagement/FederatedCredentialManagementTest.java

@@ -138,4 +138,35 @@ void testSelectAccount() {
     response = jsAwareDriver.executeScript("return await promise");
     assertThat(response).asInstanceOf(MAP).containsEntry("token", "a token");
   }
+
+  @Test
+  @NotYetImplemented(
+      value = CHROME,
+      reason = "https://github.com/SeleniumHQ/selenium/pull/12096#issuecomment-2017760822")
+  void testClickDialogButton() {
+    fedcmDriver.setDelayEnabled(false);
+    assertNull(fedcmDriver.getFederatedCredentialManagementDialog());
+
+    Object response = triggerFedCm();
+
+    waitForDialog();
+
+    FederatedCredentialManagementDialog dialog =
+        fedcmDriver.getFederatedCredentialManagementDialog();
+
+    assertEquals("Sign in to localhost with localhost", dialog.getTitle());
+    assertEquals("AccountChooser", dialog.getDialogType());
+
+    dialog.clickButton(dialog.BUTTON_PRIVACY_POLICY, 1);
+    int windowCount = localDriver.getWindowHandles().size();
+    WebDriverWait wait = new WebDriverWait(localDriver, Duration.ofSeconds(5));
+    wait.until(
+        driver ->
+            driver.getWindowHandles().size() > windowCount);
+
+    dialog.selectAccount(0);
+
+    response = jsAwareDriver.executeScript("return await promise");
+    assertThat(response).asInstanceOf(MAP).containsEntry("token", "a token");
+  }
 }