Only close popup bubble when a tab switch happens.

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 1566 matching lines @@
 }
 
 - (void)setFrameOfActiveTab:(NSRect)frame {
   NSView* view = [self activeTabView];
   NSValue* identifier = [NSValue valueWithPointer:view];
   [targetFrames_ setObject:[NSValue valueWithRect:frame]
                     forKey:identifier];
   [view setFrame:frame];
 }
 
+- (TabStripModel*)tabStripModel {
+  return tabStripModel_;
+}
+
 - (NSView*)activeTabView {
   int activeIndex = tabStripModel_->active_index();
   // Take closing tabs into account. They can't ever be selected.
   activeIndex = [self indexFromModelIndex:activeIndex];
   return [self viewAtIndex:activeIndex];
 }
 
 // Find the model index based on the x coordinate of the placeholder. If there
 // is no placeholder, this returns the end of the tab strip. Closing tabs are
 // not considered in computing the index.
@@ skipping 510 matching lines @@
   NSInteger index = [self indexFromModelIndex:modelIndex];
   BrowserWindowController* controller =
       (BrowserWindowController*)[[switchView_ window] windowController];
   DCHECK(index >= 0);
   if (index >= 0) {
     [controller setTab:[self viewAtIndex:index] isDraggable:YES];
   }
 }
 
 @end