Tabs API is usable without tabs permission.

chrome/browser/extensions/event_router.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/extensions/event_router.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/runtime/runtime_api.h"
 #include "chrome/browser/extensions/api/web_request/web_request_api.h"
 #include "chrome/browser/extensions/extension_devtools_manager.h"
 #include "chrome/browser/extensions/extension_host.h"
+#include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/extensions/extension_processes_api.h"
 #include "chrome/browser/extensions/extension_processes_api_constants.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/lazy_background_task_queue.h"
 #include "chrome/browser/extensions/process_map.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/common/chrome_notification_types.h"
@@ skipping 410 matching lines @@
       !process_map->Contains(extension->id(), process->GetID())) {
     return;
   }
 
   ListValue* event_args = NULL;
   if (!CanDispatchEventToProfile(listener_profile, extension,
                                  event, &event_args)) {
     return;
   }
 
+  // If the "tabs" permission is not present, we need to strip the Tab argument
+  // of sensitive data.
+  ExtensionTabUtil::MaybeStripEventArgsOfSensitiveData(

[Aaron Boodman, 2012/08/30 05:45:48]

Can we go back to only adding it in the first place if needed?

[chebert, 2012/08/30 23:17:20]

Done.

+      event->event_name, extension, event_args);
+
   DispatchExtensionMessage(process, extension_id,
                            event->event_name, event_args,
                            event->event_url, event->user_gesture,
                            event->info);
   IncrementInFlightEvents(listener_profile, extension);
 }
 
 bool EventRouter::CanDispatchEventToProfile(Profile* profile,
                                             const Extension* extension,
                                             const linked_ptr<Event>& event,
@@ skipping 60 matching lines @@
   if (host->extension() && host->extension()->has_lazy_background_page())
     pm->DecrementLazyKeepaliveCount(host->extension());
 }
 
 void EventRouter::DispatchPendingEvent(const linked_ptr<Event>& event,
                                        ExtensionHost* host) {
   if (!host)
     return;
 
   if (listeners_.HasProcessListener(host->render_process_host(),
-                                    host->extension()->id()))
+                                    host->extension()->id())) {
     DispatchEventToProcess(host->extension()->id(),
                            host->render_process_host(), event);
+  }
 }
 
 void EventRouter::Observe(int type,
                           const content::NotificationSource& source,
                           const content::NotificationDetails& details) {
   switch (type) {
     case content::NOTIFICATION_RENDERER_PROCESS_TERMINATED:
     case content::NOTIFICATION_RENDERER_PROCESS_CLOSED: {
       content::RenderProcessHost* renderer =
           content::Source<content::RenderProcessHost>(source).ptr();
@@ skipping 63 matching lines @@
       event_args(event_args.Pass()),
       event_url(event_url),
       restrict_to_profile(restrict_to_profile),
       cross_incognito_args(NULL),
       user_gesture(user_gesture),
       info(info) {}
 
 Event::~Event() {}
 
 }  // namespace extensions