Instant: Use only one hidden WebContents per profile.

chrome/browser/ui/views/frame/browser_view.cc

 // Copyright 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/frame/browser_view.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
@@ skipping 1517 matching lines @@
     bookmark_bar_view_->SetBookmarkBarState(
         browser_->bookmark_bar_state(),
         BookmarkBar::DONT_ANIMATE_STATE_CHANGE);
   }
   UpdateUIForContents(new_contents);
 
   // Layout for DevTools _before_ setting the main WebContents to avoid
   // toggling the size of the main WebContents.
   UpdateDevToolsForContents(new_contents);
 
-  if (change_tab_contents) {
+  if (change_tab_contents)
     contents_container_->SetWebContents(new_contents);
-    contents_->MaybeStackOverlayAtTop();
-  }
 
   if (!browser_->tab_strip_model()->closing_all() && GetWidget()->IsActive() &&
       GetWidget()->IsVisible()) {
     // We only restore focus if our window is visible, to avoid invoking blur
     // handlers when we are eventually shown.
     new_contents->GetView()->RestoreFocus();
   }
 
   // Update all the UI bits.
   UpdateTitleBar();
@@ skipping 1156 matching lines @@
 
   Browser* modal_browser =
       chrome::FindBrowserWithWebContents(active_dialog->web_contents());
   if (modal_browser && (browser_ != modal_browser)) {
     modal_browser->window()->FlashFrame(true);
     modal_browser->window()->Activate();
   }
 
   AppModalDialogQueue::GetInstance()->ActivateModalDialog();
 }