Add request_id to HttpRequestInfo and pass it to the NetworkDelegate for events.

net/url_request/url_request.cc

Index: net/url_request/url_request.cc
diff --git a/net/url_request/url_request.cc b/net/url_request/url_request.cc
index 099b57b322344d4fafa49420301a288035a48249..2b20df40c2a949b6472336538654cc1c57c81926 100644
--- a/net/url_request/url_request.cc
+++ b/net/url_request/url_request.cc
@@ -43,7 +43,8 @@ void StripPostSpecificHeaders(net::HttpRequestHeaders* headers) {
 }
 
 // This counter keeps track of the identifiers used for URL requests so far.
-uint64 g_next_url_request_identifier = 0;
+// 0 is reserved to represent an invalid ID.
+uint64 g_next_url_request_identifier = 1;
 
 // This lock protects g_next_url_request_identifier.
 base::Lock g_next_url_request_identifier_lock;
@@ -131,6 +132,9 @@ URLRequest::URLRequest(const GURL& url, Delegate* delegate)
 }
 
 URLRequest::~URLRequest() {
+  if (context_ && context_->network_delegate())
+    context_->network_delegate()->NotifyURLRequestDestroyed(this);
+
   if (before_request_callback_)
     before_request_callback_->Cancel();