Reland "[Empties] Enable the IllustratedEmptyStates field trial testing config."

This is a reland of 74b8ec6f

Original change's description:
> [Empties] Enable the IllustratedEmptyStates field trial testing config.
> 
> Change-Id: I664fa63b5b69369cb69fb4b87463ba3bb4cfc94d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2386295
> Reviewed-by: Sergio Collazos <sczs@chromium.org>
> Reviewed-by: Steven Holte <holte@chromium.org>
> Commit-Queue: sebsg <sebsg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#805136}

Change-Id: Ieb3e461efb4c55e7ef601417819cc4470e8fe4cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2401398
Commit-Queue: sebsg <sebsg@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Auto-Submit: sebsg <sebsg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807867}

ios/chrome/browser/ui/authentication/signin_earl_grey_ui.mm

@@ -152,11 +152,15 @@ using chrome_test_util::SignOutAccountsButton;
 + (void)verifySigninPromoVisibleWithMode:(SigninPromoViewMode)mode
                              closeButton:(BOOL)closeButton {
   [ChromeEarlGreyUI waitForAppToIdle];
-  [[EarlGrey
-      selectElementWithMatcher:grey_allOf(
-                                   grey_accessibilityID(kSigninPromoViewId),
-                                   grey_sufficientlyVisible(), nil)]
-      assertWithMatcher:grey_notNil()];
+
+  // The sign-in promo is not visible when showing illustrated empty states.
+  if (![ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
+    [[EarlGrey
+        selectElementWithMatcher:grey_allOf(
+                                     grey_accessibilityID(kSigninPromoViewId),
+                                     grey_sufficientlyVisible(), nil)]
+        assertWithMatcher:grey_notNil()];
+  }
   [[EarlGrey
       selectElementWithMatcher:grey_allOf(PrimarySignInButton(),
                                           grey_sufficientlyVisible(), nil)]
@@ -169,10 +173,13 @@ using chrome_test_util::SignOutAccountsButton;
           assertWithMatcher:grey_nil()];
       break;
     case SigninPromoViewModeWarmState:
-      [[EarlGrey
-          selectElementWithMatcher:grey_allOf(SecondarySignInButton(),
-                                              grey_sufficientlyVisible(), nil)]
-          assertWithMatcher:grey_notNil()];
+      if (![ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
+        [[EarlGrey
+            selectElementWithMatcher:grey_allOf(SecondarySignInButton(),
+                                                grey_sufficientlyVisible(),
+                                                nil)]
+            assertWithMatcher:grey_notNil()];
+      }
       break;
   }
   if (closeButton) {

ios/chrome/browser/ui/bookmarks/bookmark_earl_grey_ui.mm

@@ -4,6 +4,7 @@
 
 #import "ios/chrome/browser/ui/bookmarks/bookmark_earl_grey_ui.h"
 
+#include "base/ios/ios_util.h"
 #include "base/mac/foundation_util.h"
 #import "base/test/ios/wait_util.h"
 #include "build/build_config.h"
@@ -361,12 +362,19 @@ id<GREYMatcher> SearchIconButton() {
 }
 
 - (void)verifyEmptyBackgroundAppears {
-  id<GREYMatcher> emptyBackground =
-      grey_accessibilityID([ChromeEarlGrey isIllustratedEmptyStatesEnabled]
-                               ? kTableViewIllustratedEmptyViewID
-                               : kBookmarkEmptyStateExplanatoryLabelIdentifier);
-  [[EarlGrey selectElementWithMatcher:emptyBackground]
-      assertWithMatcher:grey_sufficientlyVisible()];
+  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
+    [[EarlGrey selectElementWithMatcher:grey_accessibilityID(
+                                            kTableViewIllustratedEmptyViewID)]
+        assertWithMatcher:grey_notNil()];
+    [[EarlGrey selectElementWithMatcher:grey_text(l10n_util::GetNSString(
+                                            IDS_IOS_BOOKMARK_EMPTY_MESSAGE))]
+        assertWithMatcher:grey_sufficientlyVisible()];
+  } else {
+    [[EarlGrey
+        selectElementWithMatcher:
+            grey_accessibilityID(kBookmarkEmptyStateExplanatoryLabelIdentifier)]
+        assertWithMatcher:grey_sufficientlyVisible()];
+  }
 }
 
 - (void)verifyEmptyState {
@@ -375,10 +383,10 @@ id<GREYMatcher> SearchIconButton() {
   id<GREYInteraction> searchBar =
       [EarlGrey selectElementWithMatcher:grey_accessibilityTrait(
                                              UIAccessibilityTraitSearchField)];
-  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
-    // With the illustrated empty state, the search bar should be hidden.
-    [searchBar assertWithMatcher:grey_nil()];
-  } else {
+  // TODO(crbug.com/1126982): Fix the search bar issue on iOS 12.4.
+  // The search bar should not be visible when the illustrated empty state is
+  // shown.
+  if (![ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
     [searchBar assertWithMatcher:grey_notNil()];
   }
 }

ios/chrome/browser/ui/bookmarks/bookmarks_egtest.mm

@@ -759,7 +759,7 @@ using chrome_test_util::TappableBookmarkNodeWithLabel;
   // Reopen bookmarks.
   [BookmarkEarlGreyUI openBookmarks];
 
-  if (base::FeatureList::IsEnabled(kIllustratedEmptyStates)) {
+  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
     // Ensure the root node is opened, by verifying that there isn't a Back
     // button in the navigation bar.
     [[EarlGrey selectElementWithMatcher:chrome_test_util::
@@ -866,7 +866,7 @@ using chrome_test_util::TappableBookmarkNodeWithLabel;
 - (void)testRootEmptyState {
   [BookmarkEarlGreyUI openBookmarks];
 
-  if (base::FeatureList::IsEnabled(kIllustratedEmptyStates)) {
+  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
     // When the user has no bookmarks, the root view should be an empty state.
     [BookmarkEarlGreyUI verifyEmptyState];
   } else {
@@ -894,7 +894,7 @@ using chrome_test_util::TappableBookmarkNodeWithLabel;
                                           BookmarksNavigationBarBackButton()]
       performAction:grey_tap()];
 
-  if (base::FeatureList::IsEnabled(kIllustratedEmptyStates)) {
+  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
     // When the user has no bookmarks, the root view should be an empty state.
     [BookmarkEarlGreyUI verifyEmptyState];
   } else {

ios/chrome/browser/ui/bookmarks/managed_bookmarks_egtest.mm

@@ -164,10 +164,7 @@ void SearchBookmarksForText(NSString* search_text) {
 - (void)testEmptyManagedBookmarks {
   [BookmarkEarlGreyUI openBookmarks];
 
-  // Mobile bookmarks exists.
-  [[EarlGrey selectElementWithMatcher:TappableBookmarkNodeWithLabel(
-                                          @"Mobile Bookmarks")]
-      assertWithMatcher:grey_notNil()];
+  [BookmarkEarlGreyUI verifyEmptyState];
 
   // Managed bookmarks folder does not exist.
   [[EarlGrey selectElementWithMatcher:TappableBookmarkNodeWithLabel(

ios/chrome/browser/ui/recent_tabs/recent_tabs_egtest.mm

@@ -144,8 +144,8 @@ id<GREYMatcher> TitleOfTestPage() {
                                                   IDS_HISTORY_TITLE)),
                                           grey_accessibilityTrait(
                                               UIAccessibilityTraitHeader),
-                                          nil)]
-      assertWithMatcher:grey_sufficientlyVisible()];
+                                          grey_sufficientlyVisible(), nil)]
+      assertWithMatcher:grey_notNil()];
 
   // Close History.
   id<GREYMatcher> exitMatcher =

ios/chrome/browser/ui/settings/google_services/accounts_table_egtest.mm

@@ -226,11 +226,17 @@ id<GREYMatcher> NoBookmarksLabel() {
 
   // Open the Bookmarks screen on the Tools menu.
   [BookmarkEarlGreyUI openBookmarks];
-  [BookmarkEarlGreyUI openMobileBookmarks];
 
   // Assert that there are no bookmarks.
-  [[EarlGrey selectElementWithMatcher:NoBookmarksLabel()]
-      assertWithMatcher:grey_notNil()];
+  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
+    // The empty background appears in the root directory if the leaf folders
+    // are empty.
+    [BookmarkEarlGreyUI verifyEmptyBackgroundAppears];
+  } else {
+    [BookmarkEarlGreyUI openMobileBookmarks];
+    [[EarlGrey selectElementWithMatcher:NoBookmarksLabel()]
+        assertWithMatcher:grey_notNil()];
+  }
 }
 
 // Tests that signing out from a managed user account clears the user's data.
@@ -249,11 +255,17 @@ id<GREYMatcher> NoBookmarksLabel() {
 
   // Open the Bookmarks screen on the Tools menu.
   [BookmarkEarlGreyUI openBookmarks];
-  [BookmarkEarlGreyUI openMobileBookmarks];
 
   // Assert that there are no bookmarks.
-  [[EarlGrey selectElementWithMatcher:NoBookmarksLabel()]
-      assertWithMatcher:grey_notNil()];
+  if ([ChromeEarlGrey isIllustratedEmptyStatesEnabled]) {
+    // The empty background appears in the root directory if the leaf folders
+    // are empty.
+    [BookmarkEarlGreyUI verifyEmptyBackgroundAppears];
+  } else {
+    [BookmarkEarlGreyUI openMobileBookmarks];
+    [[EarlGrey selectElementWithMatcher:NoBookmarksLabel()]
+        assertWithMatcher:grey_notNil()];
+  }
 }
 
 // Tests that given two accounts A and B that are available on the device -

testing/variations/fieldtrial_testing_config.json

@@ -3562,6 +3562,21 @@
             ]
         }
     ],
+    "IllustratedEmptyStates": [
+        {
+            "platforms": [
+                "ios"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "IllustratedEmptyStates"
+                    ]
+                }
+            ]
+        }
+    ],
     "IncludeBetaForumMenuItem": [
         {
             "platforms": [