Remove DCHECK in popupMenuCoordinator

This CL removes the DCHECK in the popupMenuCoordinator in the callback
at the end of the presentation of the popup menu.
The DCHECK can be triggered by dismissing the popup menu before the end
of the animation.

Bug: 834957
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: Ic507735290e56ab80b3ae7b9e9f74abf0ae35722
Reviewed-on: https://chromium-review.googlesource.com/1025096Reviewed-by: Olivier Robin <olivierrobin@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#553095}

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

@@ -123,7 +123,9 @@ PopupMenuCommandType CommandTypeFromPopupType(PopupMenuType type) {
 #pragma mark - ContainedPresenterDelegate
 
 - (void)containedPresenterDidPresent:(id<ContainedPresenter>)presenter {
-  DCHECK(presenter == self.presenter);
+  if (presenter != self.presenter)
+    return;
+
   if (self.requestStartTime != 0) {
     base::TimeDelta elapsed = base::TimeDelta::FromSecondsD(
         [NSDate timeIntervalSinceReferenceDate] - self.requestStartTime);