[stacked tabs] Fix stacking logic with 'open link in new tab'

chrome/browser/ui/views/tabs/stacked_tab_strip_layout.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_TABS_STACKED_TAB_STRIP_LAYOUT_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_STACKED_TAB_STRIP_LAYOUT_H_
 
 #include <algorithm>
 
 #include "base/macros.h"
@@ skipping 85 matching lines @@
  private:
   friend class StackedTabStripLayoutTest;
 
   // Sets the x-coordinate normal tabs start at, width pinned tab count and
   // active index at once.
   void Reset(int x, int width, int pinned_tab_count, int active_index);
 
   // Resets to an ideal layout state.
   void ResetToIdealState();
 
-  // Makes |index| visible. This is used when a new tab is added that isn't
-  // active.
+  // Makes all tabs between the active tab and |index| (inclusive) visible. If
+  // this is not possible, then |index| is made visible and a stack forms
+  // immediately to the right of the active tab. This is used when a new tab is
+  // added that isn't active.
   void MakeVisible(int index);
 
   // Returns the x-coordinate for the active tab constrained by the current tab
   // counts.
   int ConstrainActiveX(int x) const;
 
   // Reset the bounds of the active tab (based on ConstrainActiveX()) and resets
   // the bounds of the remaining tabs by way of LayoutUsingCurrent*.
   void SetActiveBoundsAndLayoutFromActiveTab();
 
@@ skipping 118 matching lines @@
   int active_index_;
 
   // X-coordinate of the first tab. This is either |x_| if there are no
   // pinned tabs, or the x-coordinate of the first pinned tab.
   int first_tab_x_;
 
   DISALLOW_COPY_AND_ASSIGN(StackedTabStripLayout);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_STACKED_TAB_STRIP_LAYOUT_H_