[Autofill Assistant] Fix details margins.

Before this patch, the spacing between the details and the payment
request UI were too large.

This patch shows/hides the caroussel when the payment request is shown.
It's an intermediate quick fix before we have the new UI architecture
and works since the payment request is shown during a script execution,
which in turn again means that the caroussel is empty. Showing the
carousel reduces the margins of the details view.

R=jdemeulenaere@chromium.org, szermatt@google.com

Bug: 806868
Change-Id: I17d5d3bf138c8a2f68b24753fde55cada50984fa
Reviewed-on: https://chromium-review.googlesource.com/c/1341542
Commit-Queue: Mathias Carlen <mcarlen@chromium.org>
Reviewed-by: Stephane Zermatten <szermatt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609723}

chrome/android/java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantUiDelegate.java

@@ -767,6 +767,9 @@ class AutofillAssistantUiDelegate {
                 webContents, paymentOptions, unusedTitle, supportedBasicCardNetworks);
         // Make sure we wrap content in the container.
         mBottomBarAnimations.setBottomBarHeightToWrapContent();
+        // Note: We show and hide (below) the carousel so that the margins are adjusted correctly.
+        // This is an intermediate adjustment before the UI refactoring.
+        mBottomBarAnimations.showCarousel();
         mPaymentRequest.show(mCarouselScroll, callback);
         enableProgressBarPulsing();
     }
@@ -776,6 +779,7 @@ class AutofillAssistantUiDelegate {
         mPaymentRequest.close();
         mPaymentRequest = null;
         mBottomBarAnimations.setBottomBarHeightToFixed();
+        mBottomBarAnimations.hideCarousel();
         disableProgressBarPulsing();
     }
 }