Fix FilesAppBrowserTest.Test/showGridViewDrive

The test was flaking because a new banner was added to Drive. This
banner has a "Learn more" button that can be used to dismiss the banner,
so click it during the test.

Bug: 1147306
Change-Id: If241639b7db35fd8a2cd6bfd87776d22c04e2874
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2538865Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Austin Tankiang <austinct@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827710}

chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

@@ -890,8 +890,7 @@ WRAPPED_INSTANTIATE_TEST_SUITE_P(
         TestCase("showGridViewDownloads").DisableFilesNg(),
         TestCase("showGridViewDownloads").InGuestMode(),
         TestCase("showGridViewDownloads").FilesNg(),
-        // Flaky test: See crbug.com/1147306
-        // TestCase("showGridViewDrive"),
+        TestCase("showGridViewDrive"),
         TestCase("showGridViewButtonSwitches"),
         TestCase("showGridViewKeyboardSelectionA11y"),
         TestCase("showGridViewTitles").FilesNg(),

ui/file_manager/integration_tests/file_manager/grid_view.js

@@ -22,11 +22,12 @@ async function showGridView(rootPath, expectedSet) {
   // Open Files app on |rootPath|.
   const appId = await setupAndWaitUntilReady(rootPath);
 
-  // Dismiss the Drive banner so Grid View can display the all entries.
+  // Dismiss the Drive banners so Grid View can display the all entries.
   if (rootPath === RootPath.DRIVE) {
     if (await isFilesNg(appId)) {
       await remoteCall.waitAndClickElement(
           appId, '.drive-welcome-wrapper .banner-close');
+      await remoteCall.waitAndClickElement(appId, '#offline-learn-more');
     }
   }