Makes the current page dim out when transitioning to instant preview.

chrome/browser/cocoa/browser_window_cocoa.mm

 // Copyright (c) 2010 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/cocoa/browser_window_cocoa.h"
 
 #include "app/l10n_util_mac.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
@@ skipping 559 matching lines @@
 }
 
 void BrowserWindowCocoa::ToggleTabStripMode() {
   [controller_ toggleTabStripDisplayMode];
 }
 
 void BrowserWindowCocoa::OpenTabpose() {
   [controller_ openTabpose];
 }
 
+void BrowserWindowCocoa::PrepareForInstant() {
+  // TODO: implement fade as done on windows.
+}
+
 void BrowserWindowCocoa::ShowInstant(TabContents* preview_contents) {
   [controller_ showInstant:preview_contents];
 }
 
 void BrowserWindowCocoa::HideInstant() {
   [controller_ hideInstant];
 }
 
 gfx::Rect BrowserWindowCocoa::GetInstantBounds() {
   // Flip coordinates based on the primary screen.
@@ skipping 33 matching lines @@
 
 NSWindow* BrowserWindowCocoa::window() const {
   return [controller_ window];
 }
 
 void BrowserWindowCocoa::UpdateSidebarForContents(TabContents* tab_contents) {
   if (tab_contents == browser_->tabstrip_model()->GetSelectedTabContents()) {
     [controller_ updateSidebarForContents:tab_contents];
   }
 }