On Linux, pick the color of the slider's thumbpart from the GTK theme....

chrome/browser/extensions/extension_host.cc

 // Copyright (c) 2006-2009 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/extensions/extension_host.h"
 
 #include <list>
 
 #include "app/l10n_util.h"
 #include "app/resource_bundle.h"
@@ skipping 397 matching lines @@
 
 void ExtensionHost::Close(RenderViewHost* render_view_host) {
   if (extension_host_type_ == ViewType::EXTENSION_POPUP) {
     NotificationService::current()->Notify(
         NotificationType::EXTENSION_HOST_VIEW_SHOULD_CLOSE,
         Source<Profile>(profile_),
         Details<ExtensionHost>(this));
   }
 }
 
-RendererPreferences ExtensionHost::GetRendererPrefs() const {
-  return platform_util::GetInitedRendererPreferences();
+RendererPreferences ExtensionHost::GetRendererPrefs(Profile* profile) const {
+  return platform_util::GetInitedRendererPreferences(profile);
 }
 
 WebPreferences ExtensionHost::GetWebkitPrefs() {
   PrefService* prefs = render_view_host()->process()->profile()->GetPrefs();
   const bool kIsDomUI = true;
   WebPreferences webkit_prefs =
       RenderViewHostDelegateHelper::GetWebkitPrefs(prefs, kIsDomUI);
   if (extension_host_type_ == ViewType::EXTENSION_POPUP)
     webkit_prefs.allow_scripts_to_close_windows = true;
   return webkit_prefs;
@@ skipping 171 matching lines @@
     window_id = ExtensionTabUtil::GetWindowId(
         const_cast<ExtensionHost* >(this)->GetBrowser());
   } else if (extension_host_type_ == ViewType::EXTENSION_BACKGROUND_PAGE) {
     // Background page is not attached to any browser window, so pass -1.
     window_id = -1;
   } else {
     NOTREACHED();
   }
   return window_id;
 }