Introduce //components/user_prefs, use to eliminate c/b/prefs dependency in Autofill.

chrome/browser/bookmarks/bookmark_expanded_state_tracker.cc

 // 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.
 
 #include "chrome/browser/bookmarks/bookmark_expanded_state_tracker.h"
 
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/bookmarks/bookmark_model.h"
 #include "chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "chrome/common/pref_names.h"
+#include "components/user_prefs/user_prefs.h"
 
 BookmarkExpandedStateTracker::BookmarkExpandedStateTracker(
     content::BrowserContext* browser_context,
     BookmarkModel* bookmark_model)
     : browser_context_(browser_context),
       bookmark_model_(bookmark_model) {
   bookmark_model->AddObserver(this);
 }
 
 BookmarkExpandedStateTracker::~BookmarkExpandedStateTracker() {
 }
 
 void BookmarkExpandedStateTracker::SetExpandedNodes(const Nodes& nodes) {
   UpdatePrefs(nodes);
 }
 
 BookmarkExpandedStateTracker::Nodes
 BookmarkExpandedStateTracker::GetExpandedNodes() {
   Nodes nodes;
   if (!bookmark_model_->IsLoaded())
     return nodes;
 
-  PrefService* prefs = PrefServiceFromBrowserContext(browser_context_);
+  PrefService* prefs =
+      components::UserPrefs::GetInstance()->Lookup(browser_context_);
   if (!prefs)
     return nodes;
 
   const ListValue* value = prefs->GetList(prefs::kBookmarkEditorExpandedNodes);
   if (!value)
     return nodes;
 
   bool changed = false;
   for (ListValue::const_iterator i = value->begin(); i != value->end(); ++i) {
     std::string value;
@@ skipping 35 matching lines @@
     int old_index,
     const BookmarkNode* node) {
   if (!node->is_folder())
     return;  // Only care about folders.
 
   // Ask for the nodes again, which removes any nodes that were deleted.
   GetExpandedNodes();
 }
 
 void BookmarkExpandedStateTracker::UpdatePrefs(const Nodes& nodes) {
-  PrefService* prefs = PrefServiceFromBrowserContext(browser_context_);
+  PrefService* prefs =
+      components::UserPrefs::GetInstance()->Lookup(browser_context_);
   if (!prefs)
     return;
 
   ListValue values;
   for (Nodes::const_iterator i = nodes.begin(); i != nodes.end(); ++i) {
     values.Set(values.GetSize(),
                new StringValue(base::Int64ToString((*i)->id())));
   }
 
   prefs->Set(prefs::kBookmarkEditorExpandedNodes, values);
 }