[WebLayer] null-check raw method data

Since the raw PaymentMethodData array may have null elements, this CL
null-check element and reject these cases.

Bug: 1152662
Change-Id: I51382071f1f90966f9ed16e88b6b3ed2691ae482
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2559642
Commit-Queue: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#831001}

components/payments/content/android/java/src/org/chromium/components/payments/PaymentRequestService.java

@@ -909,6 +909,7 @@ public class PaymentRequestService
         if (methodDataList.length == 0) return null;
         Map<String, PaymentMethodData> result = new ArrayMap<>();
         for (PaymentMethodData methodData : methodDataList) {
+            if (methodData == null) return null;
             String methodName = methodData.supportedMethod;
             if (TextUtils.isEmpty(methodName)) return null;
             result.put(methodName, methodData);