PaymentRequest JS should be injected only if PaymentRequest is enabled.

ios/chrome/browser/payments/payment_request_manager.mm

Index: ios/chrome/browser/payments/payment_request_manager.mm
diff --git a/ios/chrome/browser/payments/payment_request_manager.mm b/ios/chrome/browser/payments/payment_request_manager.mm
index b3565d766578ca8268976046475c4fed96b2a101..0673ad7223d86bd9c56a9fbe3ba856db3437db5f 100644
--- a/ios/chrome/browser/payments/payment_request_manager.mm
+++ b/ios/chrome/browser/payments/payment_request_manager.mm
@@ -203,10 +203,12 @@ const std::string kCommandPrefix = "paymentRequest";
 }
 
 - (void)initializeWebViewForPaymentRequest {
-  DCHECK(_webStateEnabled);
+  if (_enabled) {
+    DCHECK(_webStateEnabled);
 
-  [_paymentRequestJsManager inject];
-  _isScriptInjected = YES;
+    [_paymentRequestJsManager inject];
+    _isScriptInjected = YES;
+  }
 }
 
 - (BOOL)handleScriptCommand:(const base::DictionaryValue&)JSONCommand {
@@ -319,10 +321,10 @@ const std::string kCommandPrefix = "paymentRequest";
 - (void)webState:(web::WebState*)webState
     didCommitNavigationWithDetails:
         (const web::LoadCommittedDetails&)load_details {
-  _isScriptInjected = NO;
   [self dismissUI];
-  [self initializeWebViewForPaymentRequest];
+  _isScriptInjected = NO;
   [self enableCurrentWebState];
+  [self initializeWebViewForPaymentRequest];
 }
 
 @end