[iOS] Fixes Bookmark FolderVC navigationBar background.

Previously the Choose Folder Bookmark VC NavigationBar
had a gray background. This was caused because the
NavigationBar clear background didn't have content under
because setEdgesForExtendedLayout was trimming the tableView.

This CL also prevents a largeTitle to be displayed whenever
this VC is pushed, following the mocks.

Bug: 855323
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I45917d2cf467dcd793ac6dfc335e10b4d1ef2eb5
Reviewed-on: https://chromium-review.googlesource.com/1171791Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582614}

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

@@ -476,6 +476,10 @@ const CGFloat kEstimatedTableSectionFooterHeight = 40;
                  selectedFolder:self.folder];
   folderViewController.delegate = self;
   self.folderViewController = folderViewController;
+  if (@available(iOS 11, *)) {
+    self.folderViewController.navigationItem.largeTitleDisplayMode =
+        UINavigationItemLargeTitleDisplayModeNever;
+  }
 
   [self.navigationController pushViewController:self.folderViewController
                                        animated:YES];

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

@@ -155,9 +155,6 @@ using bookmarks::BookmarkNode;
   [super viewDidLoad];
   [super loadModel];
 
-  if ([self respondsToSelector:@selector(setEdgesForExtendedLayout:)]) {
-    [self setEdgesForExtendedLayout:UIRectEdgeNone];
-  }
   self.view.accessibilityIdentifier =
       kBookmarkFolderPickerViewContainerIdentifier;
   self.title = l10n_util::GetNSString(IDS_IOS_BOOKMARK_CHOOSE_GROUP_BUTTON);
@@ -173,6 +170,7 @@ using bookmarks::BookmarkNode;
     doneItem.accessibilityIdentifier =
         kBookmarkFolderEditNavigationBarDoneButtonIdentifier;
     self.navigationItem.rightBarButtonItem = doneItem;
+    [self setEdgesForExtendedLayout:UIRectEdgeNone];
   }
 
   if (self.allowsCancel) {