Fix omnibox popup on iPhone X screen rotation.

Bug: 784841, 786552
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I9469e3b2d69135ff7e39977ef0f50b7cb4ac72a4
Reviewed-on: https://chromium-review.googlesource.com/777585Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517821}

ios/chrome/browser/ui/toolbar/web_toolbar_controller.mm

@@ -2311,6 +2311,14 @@ using ios::material::TimingFunction;
   }
 }
 
+- (void)viewDidLayoutSubviews {
+  [super viewDidLayoutSubviews];
+
+  // The popup positions itself as a static frame below the web toolbar.  This
+  // will no longer be necessary post omnibox popup boxing.
+  _popupView->UpdatePopupAppearance();
+}
+
 @end
 
 #pragma mark - Testing only.