[ios] Update tab strip position on safe area changes.

Bug: 907467
Change-Id: I508359926472d5bfcda2c7564fc3d550f77e8a2b
Reviewed-on: https://chromium-review.googlesource.com/c/1350204Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610848}

ios/chrome/browser/ui/browser_view_controller.mm

@@ -1654,6 +1654,11 @@ applicationCommandEndpoint:(id<ApplicationCommands>)applicationCommandEndpoint
   if ([self isTabNativePage:currentTab]) {
     [currentTab.webController.view setNeedsLayout];
   }
+
+  // Update the tab strip placement.
+  if (self.tabStripView) {
+    [self showTabStripView:self.tabStripView];
+  }
 }
 
 - (void)viewDidLayoutSubviews {