Revert r9953 since it caused regressions like:

chrome/browser/views/tabs/tab_renderer.cc

 // Copyright (c) 2006-2008 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 <limits>
 
 #include "chrome/browser/views/tabs/tab_renderer.h"
 
 #include "chrome/browser/browser.h"
 #include "chrome/browser/profile.h"
@@ skipping 167 matching lines @@
 // TabCloseButton
 //
 //  This is a Button subclass that causes middle clicks to be forwarded to the
 //  parent View by explicitly not handling them in OnMousePressed.
 class TabCloseButton : public views::Button {
  public:
   TabCloseButton() : Button() {}
   virtual ~TabCloseButton() {}
 
   virtual bool OnMousePressed(const views::MouseEvent& event) {
+    LOG(WARNING) << "MOUSE PRESSED";
     return !event.IsOnlyMiddleMouseButton();
   }
 
   // We need to let the parent know about mouse state so that it
   // can highlight itself appropriately. Note that Exit events
   // fire before Enter events, so this works.
   virtual void OnMouseEntered(const views::MouseEvent& event) {
     BaseButton::OnMouseEntered(event);
     GetParent()->OnMouseEntered(event);
   }
@@ skipping 496 matching lines @@
 }
 
 void TabRenderer::DisplayCrashedFavIcon() {
   should_display_crashed_favicon_ = true;
 }
 
 void TabRenderer::ResetCrashedFavIcon() {
   should_display_crashed_favicon_ = false;
 }