Revert of [Sync] Stop accessing BrowserContextKeyedServiceFactory on non-UI thread.

chrome/browser/extensions/api/storage/settings_sync_util.cc

Index: chrome/browser/extensions/api/storage/settings_sync_util.cc
diff --git a/chrome/browser/extensions/api/storage/settings_sync_util.cc b/chrome/browser/extensions/api/storage/settings_sync_util.cc
index 36169c896473c0497d1a8e0db9c9df027b42573f..e29718c43f4a593c99230337ba1b709fa4e24205 100644
--- a/chrome/browser/extensions/api/storage/settings_sync_util.cc
+++ b/chrome/browser/extensions/api/storage/settings_sync_util.cc
@@ -4,7 +4,6 @@
 
 #include "chrome/browser/extensions/api/storage/settings_sync_util.h"
 
-#include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/storage/sync_value_store_cache.h"
@@ -14,10 +13,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "extensions/browser/api/storage/storage_frontend.h"
 
-using base::WeakPtr;
 using content::BrowserThread;
-using syncer::ModelType;
-using syncer::SyncableService;
 
 namespace extensions {
 
@@ -48,19 +44,13 @@
       extension_id, key, value, specifics->mutable_extension_setting());
 }
 
-WeakPtr<SyncableService> GetSyncableService(WeakPtr<SyncValueStoreCache> cache,
-                                            ModelType type) {
-  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
-  return cache.get() ? cache->GetSyncableService(type)->AsWeakPtr()
-                     : WeakPtr<SyncableService>();
-}
-
 }  // namespace
 
-syncer::SyncData CreateData(const std::string& extension_id,
-                            const std::string& key,
-                            const base::Value& value,
-                            ModelType type) {
+syncer::SyncData CreateData(
+    const std::string& extension_id,
+    const std::string& key,
+    const base::Value& value,
+    syncer::ModelType type) {
   sync_pb::EntitySpecifics specifics;
   switch (type) {
     case syncer::EXTENSION_SETTINGS:
@@ -87,29 +77,32 @@
       extension_id + "/" + key, key, specifics);
 }
 
-syncer::SyncChange CreateAdd(const std::string& extension_id,
-                             const std::string& key,
-                             const base::Value& value,
-                             ModelType type) {
+syncer::SyncChange CreateAdd(
+    const std::string& extension_id,
+    const std::string& key,
+    const base::Value& value,
+    syncer::ModelType type) {
   return syncer::SyncChange(
       FROM_HERE,
       syncer::SyncChange::ACTION_ADD,
       CreateData(extension_id, key, value, type));
 }
 
-syncer::SyncChange CreateUpdate(const std::string& extension_id,
-                                const std::string& key,
-                                const base::Value& value,
-                                ModelType type) {
+syncer::SyncChange CreateUpdate(
+    const std::string& extension_id,
+    const std::string& key,
+    const base::Value& value,
+    syncer::ModelType type) {
   return syncer::SyncChange(
       FROM_HERE,
       syncer::SyncChange::ACTION_UPDATE,
       CreateData(extension_id, key, value, type));
 }
 
-syncer::SyncChange CreateDelete(const std::string& extension_id,
-                                const std::string& key,
-                                ModelType type) {
+syncer::SyncChange CreateDelete(
+    const std::string& extension_id,
+    const std::string& key,
+    syncer::ModelType type) {
   base::DictionaryValue no_value;
   return syncer::SyncChange(
       FROM_HERE,
@@ -117,17 +110,14 @@
       CreateData(extension_id, key, no_value, type));
 }
 
-syncer::SyncClient::ServiceProvider GetSyncableServiceProvider(
-    content::BrowserContext* context,
-    ModelType type) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+syncer::SyncableService* GetSyncableService(content::BrowserContext* context,
+                                            syncer::ModelType type) {
+  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   DCHECK(type == syncer::APP_SETTINGS || type == syncer::EXTENSION_SETTINGS);
   StorageFrontend* frontend = StorageFrontend::Get(context);
   SyncValueStoreCache* sync_cache = static_cast<SyncValueStoreCache*>(
       frontend->GetValueStoreCache(settings_namespace::SYNC));
-  // We must rely on our caller to guarantee that sync_cache->AsWeakPtr() is a
-  // valid call right now, and that shutdown has not begun.
-  return base::Bind(&GetSyncableService, sync_cache->AsWeakPtr(), type);
+  return sync_cache->GetSyncableService(type);
 }
 
 }  // namespace settings_sync_util