[WIP] Pretend-to-preconnect for {mouse,touch}-event triggers.

net/http/http_stream_factory_impl_job.cc

Index: net/http/http_stream_factory_impl_job.cc
diff --git a/net/http/http_stream_factory_impl_job.cc b/net/http/http_stream_factory_impl_job.cc
index 680cd321227ff79cc89690419f7fa497ec4bc601..d72272786b2d22a53a2f886e48683d963951bd6f 100644
--- a/net/http/http_stream_factory_impl_job.cc
+++ b/net/http/http_stream_factory_impl_job.cc
@@ -766,19 +766,43 @@ int HttpStreamFactoryImpl::Job::DoInitConnection() {
   }
 
   if (IsPreconnecting()) {
-    return PreconnectSocketsForHttpRequest(
-        origin_url_,
-        request_info_.extra_headers,
-        request_info_.load_flags,
-        priority_,
-        session_,
-        proxy_info_,
-        ShouldForceSpdySSL(),
-        want_spdy_over_npn,
-        server_ssl_config_,
-        proxy_ssl_config_,
-        net_log_,
-        num_streams_);
+    HttpRequestInfo::RequestMotivation motivation = request_info_.motivation;
+    if(motivation == HttpRequestInfo::MOUSE_OVER_MOTIVATED ||
+       motivation == HttpRequestInfo::MOUSE_DOWN_MOTIVATED ||
+       motivation == HttpRequestInfo::TAP_UNCONFIRMED_MOTIVATED ||
+       motivation == HttpRequestInfo::TAP_DOWN_MOTIVATED) {

[mmenke, 2013/05/01 16:55:08]

Different behaviors based on motivation really doesn't belong in net (I'd argue
motivations don't belong in net, either, though, admittedly, they're already
there).

I think a load flag would make much more sense.  Then you could also get rid of
PretendToPreconnectSocketsForHttpRequest, and there would be no requirement that
it be used for exactly this set of motivations, which is somewhat strange.

+      int would_have_been_connected =
+          PretendToPreconnectSocketsForHttpRequest(
+              origin_url_,
+              request_info_.extra_headers,
+              request_info_.load_flags,
+              priority_,
+              session_,
+              proxy_info_,
+              ShouldForceSpdySSL(),
+              want_spdy_over_npn,
+              server_ssl_config_,
+              proxy_ssl_config_,
+              net_log_,
+              num_streams_);
+      int key = motivation * 2 + (would_have_been_connected > 0 ? 1 : 0);
+      UMA_HISTOGRAM_ENUMERATION("Net.PretendToPreconnect",
+                                key, HttpRequestInfo::MAX_MOTIVATED * 2);
+      return OK;
+    } else
+      return PreconnectSocketsForHttpRequest(
+          origin_url_,
+          request_info_.extra_headers,
+          request_info_.load_flags,
+          priority_,
+          session_,
+          proxy_info_,
+          ShouldForceSpdySSL(),
+          want_spdy_over_npn,
+          server_ssl_config_,
+          proxy_ssl_config_,
+          net_log_,
+          num_streams_);
   } else {
     // If we can't use a SPDY session, don't both checking for one after
     // the hostname is resolved.