[iOS] Change the NTP animation of the location bar

This CL changes the way to NTP is animating the appearance of the
location bar in the toolbar when the device has a regular width.
It uses a transform instead of changing the bottom constraint of the
location bar.

Bug: 906176
Change-Id: Ia110cafd9d2093a82487b2e3c342337c8cf7ef12
Reviewed-on: https://chromium-review.googlesource.com/c/1341911Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609340}

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

@@ -78,8 +78,13 @@
 - (void)setScrollProgressForTabletOmnibox:(CGFloat)progress {
   [super setScrollProgressForTabletOmnibox:progress];
 
-  self.view.locationBarBottomConstraint.constant =
-      [self verticalMarginForLocationBarForFullscreenProgress:1] * progress;
+  if (progress == 1) {
+    self.view.locationBarContainer.transform = CGAffineTransformIdentity;
+  } else {
+    self.view.locationBarContainer.transform = CGAffineTransformMakeTranslation(
+        0, [self verticalMarginForLocationBarForFullscreenProgress:1] *
+               (progress - 1));
+  }
   self.view.locationBarContainer.alpha = progress;
 
   // When the locationBarContainer is hidden, show the |fakeOmniboxTarget|.