Revert of PaymentRequest: Introduce PaymentDetailsInit and PaymentDetailsUpdate.

components/payments/content/payment_details_validation.cc

Index: components/payments/content/payment_details_validation.cc
diff --git a/components/payments/content/payment_details_validation.cc b/components/payments/content/payment_details_validation.cc
index 351e82c961b48e31c3ea659311150ec3bd1670d8..3933c1c3337b9d0ef0239913cd2e8abffd476cee 100644
--- a/components/payments/content/payment_details_validation.cc
+++ b/components/payments/content/payment_details_validation.cc
@@ -40,7 +40,7 @@
     return false;
   }
 
-  if (total && item->amount->currency != total->amount->currency) {
+  if (item->amount->currency != total->amount->currency) {
     *error_message = "Currencies must all be equal";
     return false;
   }
@@ -142,15 +142,18 @@
 
 bool validatePaymentDetails(const mojom::PaymentDetailsPtr& details,
                             std::string* error_message) {
-  if (details->total) {
-    if (!validateShippingOptionOrPaymentItem(details->total, details->total,
-                                             error_message))
-      return false;
+  if (details->total.is_null()) {
+    *error_message = "Must specify total";
+    return false;
+  }
 
-    if (details->total->amount->value[0] == '-') {
-      *error_message = "Total amount value should be non-negative";
-      return false;
-    }
+  if (!validateShippingOptionOrPaymentItem(details->total, details->total,
+                                           error_message))
+    return false;
+
+  if (details->total->amount->value[0] == '-') {
+    *error_message = "Total amount value should be non-negative";
+    return false;
   }
 
   if (details->display_items.size()) {