[SxS] Don't animate tabs when reversing contents of a split

Bug: 415072154
Change-Id: I3d539a0e9ff0e6fee377f32f2c26c07a90e38bb5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6609189
Reviewed-by: Shibalik Mohapatra <shibalik@chromium.org>
Commit-Queue: Eshwar Stalin <estalin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1468301}
diff --git a/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc b/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
index 1e8c3ca..5677379 100644
--- a/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
+++ b/chrome/browser/ui/views/tabs/browser_tab_strip_controller.cc
@@ -1034,6 +1034,7 @@
         std::back_inserter(split_indices),
         [](const std::pair<tabs::TabInterface*, int>& p) { return p.second; });
     tabstrip_->OnSplitContentsChanged(split_indices);
+    tabstrip_->StopAnimating(true);
   }
 }