[Extensions] Short-circuit activity logging if not enabled

chrome/browser/extensions/api/chrome_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 CHROME_BROWSER_EXTENSIONS_API_CHROME_EXTENSIONS_API_CLIENT_H_
 #define CHROME_BROWSER_EXTENSIONS_API_CHROME_EXTENSIONS_API_CLIENT_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "extensions/browser/api/extensions_api_client.h"
@@ skipping 22 matching lines @@
   std::unique_ptr<guest_view::GuestViewManagerDelegate>
   CreateGuestViewManagerDelegate(
       content::BrowserContext* context) const override;
   std::unique_ptr<MimeHandlerViewGuestDelegate>
   CreateMimeHandlerViewGuestDelegate(
       MimeHandlerViewGuest* guest) const override;
   WebViewGuestDelegate* CreateWebViewGuestDelegate(
       WebViewGuest* web_view_guest) const override;
   WebViewPermissionHelperDelegate* CreateWebViewPermissionHelperDelegate(
       WebViewPermissionHelper* web_view_permission_helper) const override;
-  WebRequestEventRouterDelegate* CreateWebRequestEventRouterDelegate()
-      const override;
+  std::unique_ptr<WebRequestEventRouterDelegate>
+  CreateWebRequestEventRouterDelegate() const override;
   scoped_refptr<ContentRulesRegistry> CreateContentRulesRegistry(
       content::BrowserContext* browser_context,
       RulesCacheDelegate* cache_delegate) const override;
   std::unique_ptr<DevicePermissionsPrompt> CreateDevicePermissionsPrompt(
       content::WebContents* web_contents) const override;
   std::unique_ptr<VirtualKeyboardDelegate> CreateVirtualKeyboardDelegate()
       const override;
   ManagementAPIDelegate* CreateManagementAPIDelegate() const override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeExtensionsAPIClient);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_CHROME_EXTENSIONS_API_CLIENT_H_