Devtools: Remove declaration without defintion

Change-Id: I5022809873bb40787087d4b62d5cc3a412170a15
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1751726
Auto-Submit: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686444}

content/browser/devtools/protocol/network_handler.h

@@ -202,10 +202,6 @@ class NetworkHandler : public DevToolsDomainHandler,
       const network::ResourceRequest& request,
       const std::string& cookie_line);
 
-  void WillSendNavigationRequest(net::HttpRequestHeaders* headers,
-                                 bool* skip_service_worker,
-                                 bool* disable_cache);
-
  private:
   void RequestIntercepted(std::unique_ptr<InterceptedRequestInfo> request_info);
   void SetNetworkConditions(network::mojom::NetworkConditionsPtr conditions);