Introduce NetworkDelegate's implementation in extensions.

extensions/browser/api/web_request/web_request_event_router_delegate.cc

Index: extensions/browser/api/web_request/web_request_event_router_delegate.cc
diff --git a/extensions/browser/api/web_request/web_request_event_router_delegate.cc b/extensions/browser/api/web_request/web_request_event_router_delegate.cc
index d649c00f4167c363756566223217067163fc4e39..54ff08078dc01e21af718bd9003aa20c99cb4c63 100644
--- a/extensions/browser/api/web_request/web_request_event_router_delegate.cc
+++ b/extensions/browser/api/web_request/web_request_event_router_delegate.cc
@@ -4,6 +4,10 @@
 
 #include "extensions/browser/api/web_request/web_request_event_router_delegate.h"
 
+#include "extensions/browser/api/web_request/web_request_api_constants.h"
+
+namespace keys = extension_web_request_api_constants;
+
 namespace extensions {
 
 WebRequestEventRouterDelegate::WebRequestEventRouterDelegate() {
@@ -11,6 +15,10 @@ WebRequestEventRouterDelegate::WebRequestEventRouterDelegate() {
 
 WebRequestEventRouterDelegate::~WebRequestEventRouterDelegate() {
 }
+void WebRequestEventRouterDelegate::ExtractExtraRequestDetails(
+      net::URLRequest* request, base::DictionaryValue* out){
+  out->SetInteger(keys::kTabIdKey, -1);
+}
 
 bool WebRequestEventRouterDelegate::OnGetMatchingListenersImplCheck(
     int tab_id, int window_id, net::URLRequest* request) {