[Extensions] Short-circuit activity logging if not enabled

extensions/browser/api/extensions_api_client.cc

 // 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.
 
 #include "extensions/browser/api/extensions_api_client.h"
 
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "extensions/browser/api/device_permissions_prompt.h"
 #include "extensions/browser/api/virtual_keyboard_private/virtual_keyboard_delegate.h"
@@ skipping 53 matching lines @@
     WebViewGuest* web_view_guest) const {
   return NULL;
 }
 
 WebViewPermissionHelperDelegate* ExtensionsAPIClient::
     CreateWebViewPermissionHelperDelegate(
         WebViewPermissionHelper* web_view_permission_helper) const {
   return new WebViewPermissionHelperDelegate(web_view_permission_helper);
 }
 
-WebRequestEventRouterDelegate*
+std::unique_ptr<WebRequestEventRouterDelegate>
 ExtensionsAPIClient::CreateWebRequestEventRouterDelegate() const {
-  return new WebRequestEventRouterDelegate();
+  return nullptr;
 }
 
 scoped_refptr<ContentRulesRegistry>
 ExtensionsAPIClient::CreateContentRulesRegistry(
     content::BrowserContext* browser_context,
     RulesCacheDelegate* cache_delegate) const {
   return scoped_refptr<ContentRulesRegistry>();
 }
 
 std::unique_ptr<DevicePermissionsPrompt>
 ExtensionsAPIClient::CreateDevicePermissionsPrompt(
     content::WebContents* web_contents) const {
   return nullptr;
 }
 
 std::unique_ptr<VirtualKeyboardDelegate>
 ExtensionsAPIClient::CreateVirtualKeyboardDelegate() const {
   return nullptr;
 }
 
 ManagementAPIDelegate* ExtensionsAPIClient::CreateManagementAPIDelegate()
     const {
   return nullptr;
 }
 
 }  // namespace extensions