[Extensions] Short-circuit activity logging if not enabled

extensions/browser/api/extensions_api_client.h

 // Copyright 2014 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 EXTENSIONS_BROWSER_API_EXTENSIONS_API_CLIENT_H_
 #define EXTENSIONS_BROWSER_API_EXTENSIONS_API_CLIENT_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 89 matching lines @@
   virtual WebViewGuestDelegate* CreateWebViewGuestDelegate(
       WebViewGuest* web_view_guest) const;
 
   // Returns a delegate for some of WebViewPermissionHelper's behavior. The
   // caller owns the returned WebViewPermissionHelperDelegate.
   virtual WebViewPermissionHelperDelegate*
   CreateWebViewPermissionHelperDelegate(
       WebViewPermissionHelper* web_view_permission_helper) const;
 
   // Creates a delegate for WebRequestEventRouter.
-  virtual WebRequestEventRouterDelegate* CreateWebRequestEventRouterDelegate()
-      const;
+  virtual std::unique_ptr<WebRequestEventRouterDelegate>
+  CreateWebRequestEventRouterDelegate() const;
 
   // TODO(wjmaclean): Remove this when (if) ContentRulesRegistry code moves
   // to extensions/browser/api.
   virtual scoped_refptr<ContentRulesRegistry> CreateContentRulesRegistry(
       content::BrowserContext* browser_context,
       RulesCacheDelegate* cache_delegate) const;
 
   // Creates a DevicePermissionsPrompt appropriate for the embedder.
   virtual std::unique_ptr<DevicePermissionsPrompt>
   CreateDevicePermissionsPrompt(content::WebContents* web_contents) const;
 
   // Returns a delegate for some of VirtualKeyboardAPI's behavior.
   virtual std::unique_ptr<VirtualKeyboardDelegate>
   CreateVirtualKeyboardDelegate() const;
 
   // Creates a delegate for handling the management extension api.
   virtual ManagementAPIDelegate* CreateManagementAPIDelegate() const;
 
   // NOTE: If this interface gains too many methods (perhaps more than 20) it
   // should be split into one interface per API.
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_EXTENSIONS_API_CLIENT_H_