[DRAFT] Allow a user to revert to their previous theme without closing infobar

chrome/browser/themes/theme_syncable_service.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/themes/theme_syncable_service.h"
 
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 200 matching lines @@
     ExtensionServiceInterface* extensions_service =
         extensions::ExtensionSystem::Get(profile_)->extension_service();
     CHECK(extensions_service);
     const extensions::Extension* extension =
         extensions_service->GetExtensionById(id, true);
     if (extension) {
       if (!extension->is_theme()) {
         DVLOG(1) << "Extension " << id << " is not a theme; aborting";
         return;
       }
-      if (!extensions_service->IsExtensionEnabled(id)) {

[pkotwicz, 2013/07/25 01:25:29]

I was mostly worried about interference with externally updated extensions here
because ThemeService::SetTheme() will enable the extension if it is not enabled.
I am pretty sure it is not a concern because the theme will only be synced if
the theme extension is enabled on another device.

-        DVLOG(1) << "Theme " << id << " is not enabled; aborting";
-        return;
-      }
-      // An enabled theme extension with the given id was found, so
-      // just set the current theme to it.
+      // A theme extension with the given id was found, so just set the current
+      // theme to it.
       theme_service_->SetTheme(extension);
     } else {
       // No extension with this id exists -- we must install it; we do
       // so by adding it as a pending extension and then triggering an
       // auto-update cycle.
       const bool kInstallSilently = true;
       if (!extensions_service->pending_extension_manager()->AddFromSync(
               id, update_url, &IsTheme, kInstallSilently)) {
         LOG(WARNING) << "Could not add pending extension for " << id;
         return;
@@ skipping 93 matching lines @@
       syncer::SyncChange(FROM_HERE, change_type,
                          syncer::SyncData::CreateLocalData(
                              kCurrentThemeClientTag, kCurrentThemeNodeTitle,
                              entity_specifics)));
 
   DVLOG(1) << "Update theme specifics from current theme: "
       << changes.back().ToString();
 
   return sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
 }