Do not animate detaching / undetaching the bookmark bar in immersive mode

chrome/browser/ui/views/frame/top_container_view.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/frame/top_container_view.h"
 
 #include "chrome/browser/ui/views/frame/browser_frame.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/frame/immersive_mode_controller.h"
 
@@ skipping 17 matching lines @@
                         static_cast<float>(y()));
   transform.ConcatTransform(translation);
 
   gfx::Point origin(parent()->GetBoundsInScreen().origin());
   transform.TransformPoint(origin);
   return gfx::Rect(origin, size());
 }
 
 gfx::Size TopContainerView::GetPreferredSize() {
   // The view wants to be as wide as its parent and tall enough to fully show
-  // its last child view.
-  int last_child_bottom =
-      child_count() > 0 ? child_at(child_count() - 1)->bounds().bottom() : 0;
-  return gfx::Size(browser_view_->width(), last_child_bottom);
+  // all its children. In particular, the bottom of the bookmark bar can be
+  // be above the bottom of the toolbar while the bookmark bar is animating.
+  int height = 0;
+  for (int i = 0; i < child_count(); ++i) {
+    int child_bottom = child_at(i)->bounds().bottom();
+    if (child_bottom > height)
+      height = child_bottom;
+  }
+  return gfx::Size(browser_view_->width(), height);
 }
 
 std::string TopContainerView::GetClassName() const {
   return "TopContainerView";
 }
 
 void TopContainerView::OnBoundsChanged(const gfx::Rect& previous_bounds) {
   ImmersiveModeController* immersive_controller =
       browser_view_->immersive_mode_controller();
   if (immersive_controller->IsEnabled())
     immersive_controller->OnTopContainerBoundsChanged();
 }
 
 void TopContainerView::PaintChildren(gfx::Canvas* canvas) {
   if (browser_view_->immersive_mode_controller()->IsRevealed()) {
     // Top-views depend on parts of the frame (themes, window buttons) being
     // painted underneath them. Clip rect has already been set to the bounds
     // of this view, so just paint the frame.
     views::View* frame = browser_view_->frame()->GetFrameView();
     frame->Paint(canvas);
   }
 
   views::View::PaintChildren(canvas);
 }