[ios] restore tab strip position on window resize

When the resize causes a change of UI (compact vs !compact)

Bug: 1076046
Change-Id: Ied57f3ddf332c7f4b44a7cd4920cb7e0f84a381c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2301971Reviewed-by: Mark Cogan <marq@chromium.org>
Commit-Queue: David Jean <djean@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789430}

ios/chrome/browser/ui/browser_view/browser_view_controller.mm

@@ -1599,6 +1599,13 @@ NSString* const kBrowserViewControllerSnackbarCategory =
     [self.tabStripCoordinator hideTabStrip:![self canShowTabStrip]];
     _fakeStatusBarView.hidden = ![self canShowTabStrip];
     [self addConstraintsToPrimaryToolbar];
+    // If tabstrip is coming back due to a window resize or screen rotation,
+    // reset the full screen controller to adjust the tabstrip position.
+    if (ShouldShowCompactToolbar(previousTraitCollection) &&
+        !ShouldShowCompactToolbar()) {
+      [self
+          updateForFullscreenProgress:self.fullscreenController->GetProgress()];
+    }
   }
 
   [self setNeedsStatusBarAppearanceUpdate];