[Sync] Switch Extension Settings DTC to use ProfilesyncComponentsFactory

chrome/browser/extensions/settings/settings_frontend.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/extensions/settings/settings_frontend.h"
 
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "base/string_number_conversions.h"
 #include "chrome/browser/extensions/extension_event_names.h"
@@ skipping 143 matching lines @@
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     BrowserThread::PostTask(
         BrowserThread::FILE,
         FROM_HERE,
         base::Bind(
             &SettingsFrontend::BackendWrapper::RunWithBackendOnFileThread,
             this,
             callback));
   }
 
+  SettingsBackend* GetBackend() const {

[not at google - send to devlin, 2012/02/16 22:58:44]

DCHECK(FILE thread).

[Nicolas Zea, 2012/02/23 00:27:58]

Done.

+    return backend_;
+  }
+
  private:
   friend class base::RefCountedThreadSafe<BackendWrapper>;
 
   BackendWrapper(
       const scoped_refptr<SettingsStorageFactory>& storage_factory,
       const SettingsStorageQuotaEnforcer::Limits& quota,
       const scoped_refptr<SettingsObserverList>& observers)
       : storage_factory_(storage_factory),
         quota_(quota),
         observers_(observers),
@@ skipping 92 matching lines @@
           observers_,
           profile_path.AppendASCII(
               ExtensionService::kSyncExtensionSettingsDirectoryName));
 }
 
 SettingsFrontend::~SettingsFrontend() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   observers_->RemoveObserver(profile_observer_.get());
 }
 
-void SettingsFrontend::RunWithSyncableService(
-    syncable::ModelType model_type, const SyncableServiceCallback& callback) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  scoped_refptr<BackendWrapper> backend;
-  switch (model_type) {
+SyncableService* SettingsFrontend::GetBackendForSync(
+    syncable::ModelType type) const {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+  std::map<settings_namespace::Namespace, BackendWrappers>::const_iterator
+      sync_backends = backends_.find(settings_namespace::SYNC);

[not at google - send to devlin, 2012/02/16 22:58:44]

How can this ever not find ::SYNC? The constructor populates it and I didn't
think it ever gets depopulated.

Is it so that backends_ has no chance of being mutated and thus implying thread
safety? I don't know if that follows, if it does then cool, maybe Fred will know
more about this (in any case I think the check below "if sync_backends ==
backends.end()" should be a DCHECK/CHECK).

Note that this class was designed to "live entirely" (from an interface
perspective) on the same thread, for brain-confidence of thread safety. It would
be nice for that not to change, but if it does, oh well.

[Nicolas Zea, 2012/02/23 00:27:58]

I was just being overcautious. Added a NOTREACHED in the else case.

[not at google - send to devlin, 2012/02/23 02:15:38]

DCHECK_NE(sync_backends, backends_.end()) would be more concise.

[Nicolas Zea, 2012/02/24 21:38:04]

Done.

+  if (sync_backends == backends_.end())
+    return NULL;
+  switch (type) {
     case syncable::APP_SETTINGS:
-      backend = backends_[settings_namespace::SYNC].app;
-      break;
-
+      return sync_backends->second.app->GetBackend();
     case syncable::EXTENSION_SETTINGS:
-      backend = backends_[settings_namespace::SYNC].extension;
-      break;
-
+      return sync_backends->second.extension->GetBackend();
     default:
       NOTREACHED();
+      return NULL;
   }
-  backend->RunWithBackend(base::Bind(&CallbackWithSyncableService, callback));
 }
 
 void SettingsFrontend::RunWithStorage(
     const std::string& extension_id,
     settings_namespace::Namespace settings_namespace,
     const StorageCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   const Extension* extension =
       profile_->GetExtensionService()->GetExtensionById(extension_id, true);
@@ skipping 45 matching lines @@
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   return observers_;
 }
 
 // BackendWrappers
 
 SettingsFrontend::BackendWrappers::BackendWrappers() {}
 SettingsFrontend::BackendWrappers::~BackendWrappers() {}
 
 }  // namespace extensions