[ios] Fixes some egtests when the UIRefresh flag is enabled.

KeyboardCommandsTestCase:
- Updates the recent tabs test now that recent tabs is always presented
  and never contained.
- Updates the recent tabs test because the a11y ID of the "Done" button
  is different when the UIRefresh flag is enabled.

RecentTabsTableTestCase:
- Properly nils out the mediator after it is disconnected.  This
  prevents a crash when launching recent tabs a second time.

BUG=825431

Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ib97c1536083fae82dcc523c8ea2787c74f92469b
Reviewed-on: https://chromium-review.googlesource.com/995617Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548061}

ios/chrome/browser/ui/BUILD.gn

@@ -523,6 +523,7 @@ source_set("eg_tests") {
     "//ios/chrome/app/strings",
     "//ios/chrome/browser/ui/commands",
     "//ios/chrome/browser/ui/ntp:ntp_controller",
+    "//ios/chrome/browser/ui/table_view",
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing:ios_test_support",

ios/chrome/browser/ui/keyboard_commands_egtest.mm

@@ -9,6 +9,7 @@
 #include "components/strings/grit/components_strings.h"
 #import "ios/chrome/browser/ui/browser_view_controller.h"
 #import "ios/chrome/browser/ui/ntp/new_tab_page_controller.h"
+#import "ios/chrome/browser/ui/table_view/table_container_constants.h"
 #include "ios/chrome/browser/ui/ui_util.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #include "ios/chrome/grit/ios_strings.h"
@@ -148,6 +149,7 @@ using chrome_test_util::RecentTabsMenuButton;
   // Open Bookmarks
   [ChromeEarlGreyUI openToolsMenu];
   [ChromeEarlGreyUI tapToolsMenuButton:chrome_test_util::BookmarksMenuButton()];
+  [[GREYUIThreadExecutor sharedInstance] drainUntilIdle];
 
   [self verifyNoKeyboardCommandsAreRegistered];
 
@@ -156,20 +158,24 @@ using chrome_test_util::RecentTabsMenuButton;
 }
 
 // Tests that keyboard commands are not registered when the Recent Tabs UI is
-// shown on iPhone and registered on iPad.
+// shown.
 - (void)testKeyboardCommands_RecentTabsPresented {
   // Open Recent Tabs
   [ChromeEarlGreyUI openToolsMenu];
   [ChromeEarlGreyUI tapToolsMenuButton:RecentTabsMenuButton()];
+  [[GREYUIThreadExecutor sharedInstance] drainUntilIdle];
 
-  if (IsIPadIdiom()) {
-    [self verifyKeyboardCommandsAreRegistered];
-  } else {
-    [self verifyNoKeyboardCommandsAreRegistered];
+  [self verifyNoKeyboardCommandsAreRegistered];
 
-    id<GREYMatcher> exit = grey_accessibilityID(@"Exit");
-    [[EarlGrey selectElementWithMatcher:exit] performAction:grey_tap()];
+  // Clean up by dismissing the recent tabs UI before ending the test. The
+  // a11y ID for the dismiss button depends on the UIRefresh experiment.
+  id<GREYMatcher> exitMatcher = nil;
+  if (IsUIRefreshPhase1Enabled()) {
+    exitMatcher = grey_accessibilityID(kTableContainerDismissButtonId);
+  } else {
+    exitMatcher = grey_accessibilityID(@"Exit");
   }
+  [[EarlGrey selectElementWithMatcher:exitMatcher] performAction:grey_tap()];
 }
 
 // Tests that when the app is opened on a web page and a key is pressed, the

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

@@ -113,6 +113,7 @@
   self.recentTabsContainerViewController = nil;
   self.recentTabsTransitioningDelegate = nil;
   [self.mediator disconnect];
+  self.mediator = nil;
 }
 
 #pragma mark - RecentTabsHandsetViewControllerCommand