Only dispatch tab events when there is someone listening

chrome/common/extensions/extension.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_COMMON_EXTENSIONS_EXTENSION_H_
 #define CHROME_COMMON_EXTENSIONS_EXTENSION_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 53 matching lines @@
   };
 
   // Icon sizes used by the extension system.
   static const int kIconSizes[];
 
   // Max size (both dimensions) for browser and page actions.
   static const int kPageActionIconMaxSize;
   static const int kBrowserActionIconMaxSize;
 
   // Each permission is a module that the extension is permitted to use.
+  static const char* kTabPermission;
+  static const char* kBookmarkPermission;
+
   static const char* kPermissionNames[];
   static const size_t kNumPermissions;
 
   struct PrivacyBlacklistInfo {
     FilePath path;  // Path to the plain-text blacklist.
   };
 
   // An NPAPI plugin included in the extension.
   struct PluginInfo {
     FilePath path;  // Path to the plugin.
@@ skipping 119 matching lines @@
     return api_permissions_;
   }
   const HostPermissions& host_permissions() const {
     return host_permissions_;
   }
 
   // Returns true if the extension has permission to access the host for the
   // specified URL.
   bool CanAccessHost(const GURL& url) const;
 
+  // Returns true if the extension has the specified API permission.
+  bool HasApiPermission(const std::string& permission) const {
+    return std::find(api_permissions_.begin(), api_permissions_.end(),
+                     permission) != api_permissions_.end();
+  }
+
   // Returns the set of hosts that the extension effectively has access to. This
   // is used in the permissions UI and is a combination of the hosts accessible
   // through content scripts and the hosts accessible through XHR.
   const std::set<std::string> GetEffectiveHostPermissions() const;
 
   // Whether the extension has access to all hosts. This is true if there is
   // a content script that matches all hosts, or if there is a host permission
   // for all hosts.
   bool HasAccessToAllHosts() const;
 
@@ skipping 160 matching lines @@
 
   // True if the background page is ready.
   bool background_page_ready_;
 
   FRIEND_TEST(ExtensionTest, LoadPageActionHelper);
 
   DISALLOW_COPY_AND_ASSIGN(Extension);
 };
 
 #endif  // CHROME_COMMON_EXTENSIONS_EXTENSION_H_