Makes the tabstrip center the active tab when transitioning from

chrome/browser/ui/views/tabs/tab_strip.cc

Index: chrome/browser/ui/views/tabs/tab_strip.cc
diff --git a/chrome/browser/ui/views/tabs/tab_strip.cc b/chrome/browser/ui/views/tabs/tab_strip.cc
index 10d92de52c9a1b0d99591f9f931ac8a5c32161ad..fee20d087f481ec11bc721038924f2ec1abfac5d 100644
--- a/chrome/browser/ui/views/tabs/tab_strip.cc
+++ b/chrome/browser/ui/views/tabs/tab_strip.cc
@@ -618,9 +618,21 @@ void TabStrip::SetLayoutType(TabStripLayoutType layout_type,
   if (layout_type == layout_type_)
     return;
 
+  const int active_index = controller_->GetActiveIndex();
+  int active_center = 0;
+  if (active_index != -1) {
+    active_center = ideal_bounds(active_index).x() +
+        ideal_bounds(active_index).width() / 2;
+  }
   layout_type_ = layout_type;
   SetResetToShrinkOnExit(false);
   SwapLayoutIfNecessary();
+  // When transitioning to stacked try to keep the active tab centered.
+  if (touch_layout_.get() && active_index != -1) {
+    touch_layout_->SetActiveTabLocation(
+        active_center - ideal_bounds(active_index).width() / 2);
+    AnimateToIdealBounds();
+  }
 }
 
 gfx::Rect TabStrip::GetNewTabButtonBounds() {