Move ownership of AppSorting from ExtensionPrefs to ExtensionSystem

extensions/shell/browser/shell_extensions_browser_client.cc

Index: extensions/shell/browser/shell_extensions_browser_client.cc
diff --git a/extensions/shell/browser/shell_extensions_browser_client.cc b/extensions/shell/browser/shell_extensions_browser_client.cc
index 623980f40a5db00cbd854df1fccbb78e3f6bd12b..62b2a5fedcdeed3654d502fd9f8c140a42330a35 100644
--- a/extensions/shell/browser/shell_extensions_browser_client.cc
+++ b/extensions/shell/browser/shell_extensions_browser_client.cc
@@ -9,7 +9,6 @@
 #include "content/public/browser/render_frame_host.h"
 #include "extensions/browser/api/extensions_api_client.h"
 #include "extensions/browser/api/generated_api_registration.h"
-#include "extensions/browser/app_sorting.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/extension_function_registry.h"
 #include "extensions/browser/mojo/service_registration.h"
@@ -156,11 +155,6 @@ bool ShellExtensionsBrowserClient::DidVersionUpdate(BrowserContext* context) {
 void ShellExtensionsBrowserClient::PermitExternalProtocolHandler() {
 }
 
-scoped_ptr<AppSorting> ShellExtensionsBrowserClient::CreateAppSorting(
-    content::BrowserContext* context) {
-  return scoped_ptr<AppSorting>(new NullAppSorting);
-}
-
 bool ShellExtensionsBrowserClient::IsRunningInForcedAppMode() {
   return false;
 }