Add a timeout if the page doesn't call complete() in a timely fashion.

ios/chrome/browser/payments/payment_request_manager.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/payments/payment_request_manager.h"
 
 #include "base/ios/ios_util.h"
 #import "base/ios/weak_nsobject.h"
 #import "base/mac/bind_objc_block.h"
 #include "base/mac/foundation_util.h"
@@ skipping 14 matching lines @@
 #import "ios/web/public/url_scheme_util.h"
 #import "ios/web/public/web_state/crw_web_view_proxy.h"
 #import "ios/web/public/web_state/js/crw_js_injection_receiver.h"
 #include "ios/web/public/web_state/url_verification_constants.h"
 #include "ios/web/public/web_state/web_state.h"
 #import "ios/web/public/web_state/web_state_observer_bridge.h"
 
 namespace {
 // Command prefix for injected JavaScript.
 const std::string kCommandPrefix = "paymentRequest";
+
+// Time interval between attempts to unblock the webview's JS event queue.
+const NSTimeInterval kNoopInterval = 0.1;
+
+// Time interval before closing the UI if the page has not yet called
+// PaymentResponse.complete().
+const NSTimeInterval kTimeoutInterval = 60.0;
+
 }  // namespace
 
 @interface PaymentRequestManager ()<CRWWebStateObserver,
                                     PaymentRequestCoordinatorDelegate> {
   // View controller used to present the PaymentRequest view controller.
   base::WeakNSObject<UIViewController> _baseViewController;
 
   // PersonalDataManager used to manage user credit cards and addresses.
   autofill::PersonalDataManager* _personalDataManager;
 
@@ skipping 13 matching lines @@
   // Boolean to track if the script has been injected in the current page. This
   // is a faster check than asking the JS controller.
   BOOL _isScriptInjected;
 
   // True when close has been called and the PaymentRequest coordinator has
   // been destroyed.
   BOOL _closed;
 
   // Coordinator used to create and present the PaymentRequest view controller.
   base::scoped_nsobject<PaymentRequestCoordinator> _paymentRequestCoordinator;
+
+  // Timer used to periodically unblock the webview's JS event queue.
+  base::scoped_nsobject<NSTimer> _unblockEventQueueTimer;
+
+  // Timer used to close the UI if the page does not call
+  // PaymentResponse.complete() in a timely fashion.
+  base::scoped_nsobject<NSTimer> _paymentResponseTimeoutTimer;
 }
 
 // Synchronous method executed by -asynchronouslyEnablePaymentRequest:
 - (void)doEnablePaymentRequest:(BOOL)enabled;
 
 // Initialize the PaymentRequest JavaScript.
 - (void)initializeWebViewForPaymentRequest;
 
 // Handler for injected JavaScript callbacks.
 - (BOOL)handleScriptCommand:(const base::DictionaryValue&)JSONCommand;
@@ skipping 189 matching lines @@
 
   [_paymentRequestCoordinator start];
 
   return YES;
 }
 
 - (BOOL)handleResponseComplete {
   // TODO(crbug.com/602666): Check that there *is* a pending response here.
   // TODO(crbug.com/602666): Indicate success or failure in the UI.
 
+  [_unblockEventQueueTimer invalidate];
+  [_paymentResponseTimeoutTimer invalidate];
+
   [self dismissUI];
 
-  // TODO(crbug.com/602666): Reject the promise on failure.
   [_paymentRequestJsManager resolveResponsePromise:nil];
 
   return YES;
 }
 
 - (void)dismissUI {
   [_paymentRequestCoordinator stop];
   _paymentRequestCoordinator.reset();
 }
 
@@ skipping 17 matching lines @@
 #pragma mark - PaymentRequestCoordinatorDelegate methods
 
 - (void)paymentRequestCoordinatorDidCancel {
   [self cancelRequest];
 }
 
 - (void)paymentRequestCoordinatorDidConfirm:
     (web::PaymentResponse)paymentResponse {
   [_paymentRequestJsManager resolveRequestPromise:paymentResponse
                                 completionHandler:nil];
+
+  // Establish a timer that periodically prompts the JS manager to execute a
+  // noop. This works around an issue where the JS event queue is blocked while
+  // presenting the Payment Request UI.
+  _unblockEventQueueTimer.reset(
+      [[NSTimer scheduledTimerWithTimeInterval:kNoopInterval
+                                        target:_paymentRequestJsManager
+                                      selector:@selector(executeNoop)
+                                      userInfo:nil
+                                       repeats:YES] retain]);
+
+  // Per the spec, if the page does not call PaymentResponse.complete() within
+  // some timeout period, user agents may behave as if the complete() method was
+  // called with no arguments.
+  _paymentResponseTimeoutTimer.reset(
+      [[NSTimer scheduledTimerWithTimeInterval:kTimeoutInterval
+                                        target:self
+                                      selector:@selector(handleResponseComplete)
+                                      userInfo:nil
+                                       repeats:NO] retain]);
 }
 
 #pragma mark - CRWWebStateObserver methods
 
 - (void)webState:(web::WebState*)webState
     didCommitNavigationWithDetails:
         (const web::LoadCommittedDetails&)load_details {
   [self dismissUI];
   _isScriptInjected = NO;
   [self enableCurrentWebState];
   [self initializeWebViewForPaymentRequest];
 }
 
 @end