Remove incorrect asserts in PaymentRequest

When creating a new contact, the AutofillContact object is created with
both null phone number and null email address. Therefore, asserts that
one of them should be not null are not correct. This patch removes these
asserts.

BUG=624211

Review-Url: https://codereview.chromium.org/2101983004
Cr-Commit-Position: refs/heads/master@{#402642}

chrome/android/java/src/org/chromium/chrome/browser/payments/AutofillContact.java

@@ -72,7 +72,6 @@ public class AutofillContact extends PaymentOption {
     private void setPhoneEmail(@Nullable String phone, @Nullable String email) {
         mPayerPhone = TextUtils.isEmpty(phone) ? null : phone;
         mPayerEmail = TextUtils.isEmpty(email) ? null : email;
-        assert mPayerPhone != null || mPayerEmail != null;
         updateLabels(mPayerPhone == null ? mPayerEmail : mPayerPhone,
                 mPayerPhone == null ? null : mPayerEmail);
     }

chrome/android/java/src/org/chromium/chrome/browser/payments/ui/PaymentOption.java

@@ -64,7 +64,6 @@ public class PaymentOption {
      * @param sublabel The new sublabel to use. Can be null.
      */
     protected void updateLabels(String label, @Nullable String sublabel) {
-        assert label != null;
         mLabel = label;
         mSublabel = sublabel;
     }