Move some of the new transient background page stuff into the extensions
namespace.

Also add ExtensionSytem::Get(Profile*) convenience wrapper.

BUG=no
TEST=no

Review URL: https://chromiumcodereview.appspot.com/9977019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@130981 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/extensions/lazy_background_task_queue.cc b/chrome/browser/extensions/lazy_background_task_queue.cc
index b5ac94d..4691c47 100644
--- a/chrome/browser/extensions/lazy_background_task_queue.cc
+++ b/chrome/browser/extensions/lazy_background_task_queue.cc
@@ -23,6 +23,8 @@
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
 
+namespace extensions {
+
 LazyBackgroundTaskQueue::LazyBackgroundTaskQueue(Profile* profile)
     : profile_(profile) {
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING,
@@ -131,3 +133,5 @@
       break;
   }
 }
+
+}  // namespace extensions