[PRImpl] Not to assert getCertificateChain

Since  mCertificateChain is provided by CertificateChainHelper,
PaymentRequestImpl should not assert its existence.

Bug: 1122148

Change-Id: I48b8ec4c6559bd3a95596d90fc2cf670ad167f87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2391725Reviewed-by: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#803986}

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

@@ -335,7 +335,6 @@ public class PaymentRequestImpl
         mTopLevelOrigin = componentPaymentRequestImpl.getTopLevelOrigin();
         assert mTopLevelOrigin != null;
         mCertificateChain = componentPaymentRequestImpl.getCertificateChain();
-        assert mCertificateChain != null;
         mIsOffTheRecord = componentPaymentRequestImpl.isOffTheRecord();
         mDelegate = delegate;
         mWebContents = componentPaymentRequestImpl.getWebContents();