Fixes another places that may trigger deletion during tab dragging

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

 // 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.
 
 #include "chrome/browser/ui/views/tabs/tab_drag_controller.h"
 
 #include <math.h>
 #include <set>
 
 #include "base/auto_reset.h"
@@ skipping 1525 matching lines @@
   waiting_for_run_loop_to_exit_ = false;
   if (end_run_loop_behavior_ == END_RUN_LOOP_CONTINUE_DRAGGING) {
     end_run_loop_behavior_ = END_RUN_LOOP_STOP_DRAGGING;
     if (tab_strip_to_attach_to_after_exit_) {
       gfx::Point point_in_screen(GetCursorScreenPoint());
       Detach(DONT_RELEASE_CAPTURE);
       Attach(tab_strip_to_attach_to_after_exit_, point_in_screen);
       // Move the tabs into position.
       MoveAttached(point_in_screen);
       attached_tabstrip_->GetWidget()->Activate();
+      // Activate may trigger a focus loss, destroying us.
+      if (!ref)
+        return;
       tab_strip_to_attach_to_after_exit_ = NULL;
     }
     DCHECK(attached_tabstrip_);
     attached_tabstrip_->GetWidget()->SetCapture(attached_tabstrip_);
   } else if (active_) {
     EndDrag(result == views::Widget::MOVE_LOOP_CANCELED ?
             END_DRAG_CANCEL : END_DRAG_COMPLETE);
   }
 }
 
@@ skipping 739 matching lines @@
 gfx::Vector2d TabDragController::GetWindowOffset(
     const gfx::Point& point_in_screen) {
   TabStrip* owning_tabstrip = (attached_tabstrip_ && detach_into_browser_) ?
       attached_tabstrip_ : source_tabstrip_;
   views::View* toplevel_view = owning_tabstrip->GetWidget()->GetContentsView();
 
   gfx::Point point = point_in_screen;
   views::View::ConvertPointFromScreen(toplevel_view, &point);
   return point.OffsetFromOrigin();
 }