Add popup menu to the tab grid button

This CL adds a popup menu to create new (incognito) tab when long
pressing the tab grid button.

Bug: 821560
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ib1a8c7ff3e82cb4422ba50f01993be5e28be275d
Reviewed-on: https://chromium-review.googlesource.com/980255Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#546054}

ios/chrome/browser/ui/popup_menu/popup_menu_coordinator.mm

@@ -94,12 +94,18 @@
 }
 
 - (void)showTabGridButtonPopup {
-  UIViewController* viewController = [[UIViewController alloc] init];
-  UILabel* label = [[UILabel alloc] init];
-  label.text = @"TabGrid";
-  viewController.view = label;
-  // TODO(crbug.com/821560): Use the tab grid menu instead of a label.
-  [self presentPopupForContent:viewController fromNamedGuide:kTabSwitcherGuide];
+  PopupMenuTableViewController* tableViewController =
+      [[PopupMenuTableViewController alloc] init];
+  tableViewController.dispatcher =
+      static_cast<id<ApplicationCommands, BrowserCommands>>(self.dispatcher);
+  tableViewController.baseViewController = self.baseViewController;
+
+  self.mediator = [[PopupMenuMediator alloc] initWithType:PopupMenuTypeTabGrid];
+  self.mediator.webStateList = self.webStateList;
+  self.mediator.popupMenu = tableViewController;
+
+  [self presentPopupForContent:tableViewController
+                fromNamedGuide:kTabSwitcherGuide];
 }
 
 - (void)searchButtonPopup {

ios/chrome/browser/ui/popup_menu/popup_menu_mediator.mm

@@ -217,6 +217,7 @@ PopupMenuToolsItem* CreateTableViewItem(int titleID,
       case PopupMenuTypeNavigationBackward:
         break;
       case PopupMenuTypeTabGrid:
+        self.items = @[ [self itemsForNewTab] ];
         break;
       case PopupMenuTypeSearch:
         break;

ios/chrome/browser/ui/toolbar/adaptive/adaptive_toolbar_view_controller.mm

@@ -77,6 +77,7 @@
   [self addLongPressGestureToView:self.view.backButton];
   [self addLongPressGestureToView:self.view.forwardButton];
   [self addLongPressGestureToView:self.view.forwardButtonTrailingPosition];
+  [self addLongPressGestureToView:self.view.tabGridButton];
 }
 
 - (void)traitCollectionDidChange:(UITraitCollection*)previousTraitCollection {
@@ -270,6 +271,8 @@
     } else {
       [self.dispatcher showTabHistoryPopupForForwardHistory];
     }
+  } else if (gesture.view == self.view.tabGridButton) {
+    [self.dispatcher showTabGridButtonPopup];
   }
 }