Notify NetworkDelegate when bytes have been sent over the network.

net/base/network_delegate.h

Index: net/base/network_delegate.h
diff --git a/net/base/network_delegate.h b/net/base/network_delegate.h
index 3a29e26c9f7695a2b7a83fe59bb73f695c6ebf97..5ec43dd9b1e6aae2c1426f658285cb21ddb07bcb 100644
--- a/net/base/network_delegate.h
+++ b/net/base/network_delegate.h
@@ -78,6 +78,7 @@ class NET_EXPORT NetworkDelegate : public base::NonThreadSafe {
                                     HttpRequestHeaders* headers);
   void NotifySendHeaders(URLRequest* request,
                          const HttpRequestHeaders& headers);
+  void NotifyNetworkBytesSent(const URLRequest& request, int64_t bytes_sent);

[mmenke, 2015/09/24 21:30:24]

While I see you put this roughly in the order it's invoked, I think this method
makes more sense just above NotifyNetworkBytesReceived (Or below, for
consistency - I'm fine, either way).  This goes for all other files as well, and
OnNetworkBytesSent and NotifyNetworkBytesSentInternal as well.

[sclittle, 2015/09/24 22:20:42]

Done.

   int NotifyHeadersReceived(
       URLRequest* request,
       const CompletionCallback& callback,
@@ -173,6 +174,16 @@ class NET_EXPORT NetworkDelegate : public base::NonThreadSafe {
   virtual void OnSendHeaders(URLRequest* request,
                              const HttpRequestHeaders& headers) = 0;
 
+  // Called when bytes are sent over the network, such as when sending request
+  // headers or uploading request body bytes. This includes localhost requests.
+  // |bytes_sent| is the number of bytes measured at the application layer that
+  // have been sent over the network for this request since the last time
+  // OnNetworkBytesSent was called. |bytes_sent| will always be greater than 0.
+  // Currently, this is only implemented for HTTP transactions, and |bytes_sent|
+  // does not include TLS overhead or TCP retransmits.
+  virtual void OnNetworkBytesSent(const URLRequest& request,
+                                  int64_t bytes_sent) = 0;
+
   // Called for HTTP requests when the headers have been received.
   // |original_response_headers| contains the headers as received over the
   // network, these must not be modified. |override_response_headers| can be set