Don't access destroyed web contents.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
index a91adcd4ba9c4518beaa2c76be66d572f6620347..1b1bf9a9964975a6b6531268585fde7466ae97bb 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/AndroidPaymentApp.java
@@ -298,6 +298,11 @@ public class AndroidPaymentApp
         assert mMethodNames.containsAll(methodDataMap.keySet());
         assert mInstrumentDetailsCallback != null;
 
+        if (mWebContents.isDestroyed()) {
+            notifyErrorInvokingPaymentApp();
+            return;
+        }
+
         WindowAndroid window = mWebContents.getTopLevelNativeWindow();
         if (window == null) {
             notifyErrorInvokingPaymentApp();