Fix NTP toolbar's dispatcher

The dispatcher wasn't set for the primary toolbar used by the NTP,
leading to bugs where the commands weren't sent to the rest of the
application.

Bug: 851930
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I17b2e015a307e993e548c4dfcbca599472503d58
Reviewed-on: https://chromium-review.googlesource.com/1110123
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569279}

ios/chrome/browser/ui/content_suggestions/content_suggestions_coordinator.mm

@@ -156,6 +156,7 @@
     self.primaryToolbarViewController =
         [[PrimaryToolbarViewController alloc] init];
     self.primaryToolbarViewController.buttonFactory = buttonFactory;
+    self.primaryToolbarViewController.dispatcher = self.dispatcher;
     [self.primaryToolbarViewController updateForSideSwipeSnapshotOnNTP:YES];
     self.headerController.toolbarViewController =
         self.primaryToolbarViewController;