Change how the insertion point for tab drags is calculated.

chrome/browser/ui/views/tabs/tab_drag_controller.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_TAB_DRAG_CONTROLLER_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_TAB_DRAG_CONTROLLER_H_
 
 #include <vector>
 
 #include "base/memory/weak_ptr.h"
@@ skipping 312 matching lines @@
   // runs a nested move loop.
   void DetachIntoNewBrowserAndRunMoveLoop(const gfx::Point& point_in_screen);
 
   // Runs a nested message loop that handles moving the current
   // Browser. |drag_offset| is the offset from the window origin and is used in
   // calculating the location of the window offset from the cursor while
   // dragging.
   void RunMoveLoop(const gfx::Vector2d& drag_offset);
 
   // Determines the index to insert tabs at. |dragged_bounds| is the bounds of
-  // the tabs being dragged, |start| the index of the tab to start looking from
-  // and |delta| the amount to increment (1 or -1).
-  int GetInsertionIndexFrom(const gfx::Rect& dragged_bounds,
-                            int start,
-                            int delta) const;
+  // the tabs being dragged, |start| the index of the tab to start looking from.
+  // The search proceeds to the end of the strip.
+  int GetInsertionIndexFrom(const gfx::Rect& dragged_bounds, int start) const;
+
+  // Like GetInsertionIndexFrom(), but searches backwards from |start| to the
+  // beginning of the strip.
+  int GetInsertionIndexFromReversed(const gfx::Rect& dragged_bounds,
+                                    int start) const;
 
   // Returns the index where the dragged WebContents should be inserted into
   // |attached_tabstrip_| given the DraggedTabView's bounds |dragged_bounds| in
   // coordinates relative to |attached_tabstrip_| and has had the mirroring
   // transformation applied.
   // NOTE: this is invoked from Attach() before the tabs have been inserted.
   int GetInsertionIndexForDraggedBounds(const gfx::Rect& dragged_bounds) const;
 
   // Returns true if |dragged_bounds| is close enough to the next stacked tab
   // so that the active tab should be dragged there.
@@ skipping 286 matching lines @@
   int attach_index_;
 
   scoped_ptr<ui::EventHandler> escape_tracker_;
 
   base::WeakPtrFactory<TabDragController> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TabDragController);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_DRAG_CONTROLLER_H_