[Android][Payment]changePaymentMethod should work with missing details

Without this cl changePaymentMethod would fail when the "details" key
did not exist in input bundle. With this change the "StringifiedDetails"
passed to changePaymentMethodfromInvokedApp()[1] will have the default
stringified empty JSON object value.

[1]https://cs.chromium.org/chromium/src/components/payments/content/android/java/src/org/chromium/components/payments/PaymentRequestUpdateEventListener.java?l=32

Bug: 1026667
Change-Id: I55ac9d3e5d6dc6923290223317164d1dfdd3faa6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2255656
Commit-Queue: Sahel Sharify <sahel@chromium.org>
Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781458}

chrome/android/javatests/src/org/chromium/chrome/browser/payments/PaymentDetailsUpdateServiceHelperTest.java

@@ -328,7 +328,8 @@ public class PaymentDetailsUpdateServiceHelperTest {
         installAndInvokePaymentApp();
         startPaymentDetailsUpdateService();
         Bundle bundle = new Bundle();
-        bundle.putString(PaymentHandlerMethodData.EXTRA_STRINGIFIED_DETAILS, "data");
+        bundle.putString(
+                PaymentHandlerMethodData.EXTRA_STRINGIFIED_DETAILS, "{\"key\": \"value\"}");
         mIPaymentDetailsUpdateService.changePaymentMethod(
                 bundle, new PaymentDetailsUpdateServiceCallback());
         verifyIsWaitingForPaymentDetailsUpdate(false);
@@ -336,6 +337,25 @@ public class PaymentDetailsUpdateServiceHelperTest {
         Assert.assertEquals(ErrorStrings.METHOD_NAME_REQUIRED, receivedErrorString());
     }
 
+    @Test
+    @MediumTest
+    @Feature({"Payments"})
+    public void testSuccessfulChangePaymentMethodWithMissingDetails() throws Throwable {
+        installAndInvokePaymentApp();
+        startPaymentDetailsUpdateService();
+        Bundle bundle = new Bundle();
+        bundle.putString(PaymentHandlerMethodData.EXTRA_METHOD_NAME, "method-name");
+        // Skip populating "PaymentHandlerMethodData.EXTRA_STRINGIFIED_DETAILS" to verify that it is
+        // not a mandatory field.
+        mIPaymentDetailsUpdateService.changePaymentMethod(
+                bundle, new PaymentDetailsUpdateServiceCallback());
+        verifyIsWaitingForPaymentDetailsUpdate(true);
+        Assert.assertTrue(mMethodChangeListenerNotified);
+        updateWithDefaultDetails();
+        verifyUpdatedDefaultDetails();
+        verifyIsWaitingForPaymentDetailsUpdate(false);
+    }
+
     @Test
     @MediumTest
     @Feature({"Payments"})

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

@@ -89,9 +89,8 @@ public class PaymentDetailsUpdateServiceHelper {
             return;
         }
 
-        @Nullable
         String stringifiedDetails = paymentHandlerMethodData.getString(
-                PaymentHandlerMethodData.EXTRA_STRINGIFIED_DETAILS);
+                PaymentHandlerMethodData.EXTRA_STRINGIFIED_DETAILS, /*defaultValue=*/"{}");
 
         if (isWaitingForPaymentDetailsUpdate() || mListener == null
                 || !mListener.changePaymentMethodFromInvokedApp(methodName, stringifiedDetails)) {