[WebLayer] Extracts trigger-skip-ui out of continueShow

Before the CL:
- CPRService#continueShow() calls
  CPRService#triggerPaymentAppUiSkipIfApplicable()

After the CL:
- PRService#continueShow() calls
  PRService#triggerPaymentAppUiSkipIfApplicable()

Bug: 1147092
Change-Id: I11a5af8815759b04738ed2f423c8a5921b4efdc1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2543131
Commit-Queue: Liquan (Max) Gu <maxlg@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828448}

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

@@ -432,9 +432,6 @@ public class ChromePaymentRequestService
                     mSpec.getRawTotal().amount.value, false /*completed*/);
         }
 
-        String error = triggerPaymentAppUiSkipIfApplicable(isUserGestureShow);
-        if (error != null) return error;
-
         if (isFinishedQueryingPaymentApps
                 && !mPaymentUiService.shouldSkipShowingPaymentRequestUi()) {
             boolean providedInformationToPaymentRequestUI =

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

@@ -958,17 +958,20 @@ public class PaymentRequestService
         triggerPaymentAppUiSkipIfApplicable();
     }
 
-    private void triggerPaymentAppUiSkipIfApplicable() {
+    // Return the error if failed, null if success.
+    @Nullable
+    private String triggerPaymentAppUiSkipIfApplicable() {
         if (!mIsFinishedQueryingPaymentApps || !mIsCurrentPaymentRequestShowing
                 || mIsShowWaitingForUpdatedDetails) {
-            return;
+            return null;
         }
         String error =
                 mBrowserPaymentRequest.triggerPaymentAppUiSkipIfApplicable(mIsUserGestureShow);
         if (error != null) {
             onShowFailed(error);
-            return;
+            return error;
         }
+        return null;
     }
 
     // Implements PaymentDetailsConverter.MethodChecker:
@@ -998,7 +1001,7 @@ public class PaymentRequestService
         String error = mBrowserPaymentRequest.continueShow(
                 mIsFinishedQueryingPaymentApps, mIsUserGestureShow);
         if (error != null) return error;
-        return null;
+        return triggerPaymentAppUiSkipIfApplicable();
     }
 
     /**