Do not invoke SetNaClArch if the hotword extension is new enough.

This would be essentially harmless, but setting 'nacl arch'
in StartPageHandler means allowing embed of the hotword plugin,
which consumes memory and CPU. Because it communicates with
the hotword extension directly, this plugin is unused at all.

BUG=393321
R=xiyuan@chromium.org

Review URL: https://codereview.chromium.org/395963002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283745 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/webui/app_list/start_page_handler.cc

@@ -177,11 +177,20 @@ void StartPageHandler::HandleInitialize(const base::ListValue* args) {
     extension_registry_observer_.Add(
         extensions::ExtensionRegistry::Get(profile));
   }
-#endif
 
+  extensions::ExtensionRegistry* registry =
+      extensions::ExtensionRegistry::Get(profile);
+  const extensions::Extension* hotword_extension =
+      registry->GetExtensionById(extension_misc::kHotwordExtensionId,
+                                 extensions::ExtensionRegistry::ENABLED);
+  if (hotword_extension &&
+      hotword_extension->version()->CompareTo(
+          base::Version(kOldHotwordExtensionVersionString)) <= 0) {
     web_ui()->CallJavascriptFunction(
         "appList.startPage.setNaclArch",
         base::StringValue(omaha_query_params::OmahaQueryParams::GetNaclArch()));
+  }
+#endif
 
   if (!app_list::switches::IsExperimentalAppListEnabled()) {
     web_ui()->CallJavascriptFunction(