Fix Secure Payment Confirmation controller logic

This patch fixes a bug in the SPC controller logic that checks for the
existence of the PaymentRequestSpec. This bug results in no UI shown
when the feature is activated.

Bug: 1133822 1127322
Change-Id: I27d1d6f2a53e859a132f2f73237a360979efe6a0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441937
Commit-Queue: Nick Burris <nburris@chromium.org>
Commit-Queue: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812575}

components/payments/content/secure_payment_confirmation_controller.cc

@@ -34,7 +34,7 @@ void SecurePaymentConfirmationController::ShowDialog() {
   NOTREACHED();
 #endif  // OS_ANDROID
 
-  if (!request_ || request_->spec())
+  if (!request_ || !request_->spec())
     return;
 
   if (!request_->state()->IsInitialized()) {