[iOS] Don't prevent toolbar contract while animating

This CL let the toolbar be contracted even if it is animating.
This is needed, because calling twice the same method could yield
different results based on the state of the device (portrait vs
landscape for example).

Bug: 900761
Change-Id: Ie3f44e871e411162bc63467d6cf5e7df3d02cc22
Reviewed-on: https://chromium-review.googlesource.com/c/1349347Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#611077}

ios/chrome/browser/ui/orchestrator/omnibox_focus_orchestrator.mm

@@ -29,18 +29,18 @@
 - (void)transitionToStateOmniboxFocused:(BOOL)omniboxFocused
                         toolbarExpanded:(BOOL)toolbarExpanded
                                animated:(BOOL)animated {
-  if (self.isAnimating) {
-    return;
-  }
-
-  self.isAnimating = animated;
-
   if (toolbarExpanded) {
     [self updateUIToExpandedState:animated];
   } else {
     [self updateUIToContractedState:animated];
   }
 
+  if (self.isAnimating) {
+    return;
+  }
+
+  self.isAnimating = animated;
+
   // Make the rest of the animation happen on the next runloop when this
   // animation have calculated the final frame for the location bar.
   // This is necessary because expanding/contracting the toolbar is actually