Tabs API is usable without tabs permission.

chrome/browser/extensions/browser_event_router.cc

Index: chrome/browser/extensions/browser_event_router.cc
diff --git a/chrome/browser/extensions/browser_event_router.cc b/chrome/browser/extensions/browser_event_router.cc
index 83347cbb9acf9f55ff020429fed77b14604b7692..62672aef11947f6d73f5c03170f5471e81f44c20 100644
--- a/chrome/browser/extensions/browser_event_router.cc
+++ b/chrome/browser/extensions/browser_event_router.cc
@@ -390,7 +390,9 @@ void BrowserEventRouter::DispatchEventWithTab(
 
   scoped_ptr<ListValue> args(new ListValue());
   args->Append(ExtensionTabUtil::CreateTabValueActive(
-      web_contents, active));
+      web_contents,
+      active,
+      profile->GetExtensionService()->extensions()->GetByID(extension_id)));
   if (!extension_id.empty()) {
     DispatchEventToExtension(profile, extension_id, event_name, args.Pass(),
                              user_gesture);
@@ -427,9 +429,9 @@ void BrowserEventRouter::DispatchTabUpdatedEvent(
   args->Append(changed_properties);
 
   // Third arg: An object containing the state of the tab.
-  args->Append(ExtensionTabUtil::CreateTabValue(contents));
-
   Profile* profile = Profile::FromBrowserContext(contents->GetBrowserContext());
+  args->Append(ExtensionTabUtil::CreateTabValue(contents, NULL /*extension*/));
+
   DispatchEvent(profile, events::kOnTabUpdated, args.Pass(),
                 EventRouter::USER_GESTURE_UNKNOWN);
 }