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

net/http/http_stream_factory_impl_job.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/http/http_stream_factory_impl_job.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
@@ skipping 748 matching lines @@
     // Disable revocation checking for HTTPS proxies since the revocation
     // requests are probably going to need to go through the proxy too.
     proxy_ssl_config_.rev_checking_enabled = false;
   }
   if (using_ssl_) {
     InitSSLConfig(origin_, &server_ssl_config_,
                   false /* not a proxy server */);
   }
 
   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.
     OnHostResolutionCallback resolution_callback = CanUseExistingSpdySession() ?
         base::Bind(&Job::OnHostResolution, session_->spdy_session_pool(),
                    GetSpdySessionKey()) :
         OnHostResolutionCallback();
     return InitSocketHandleForHttpRequest(
         origin_url_, request_info_.extra_headers, request_info_.load_flags,
         priority_, session_, proxy_info_, ShouldForceSpdySSL(),
@@ skipping 563 matching lines @@
       (net::LOAD_MAIN_FRAME | net::LOAD_SUB_FRAME | net::LOAD_PREFETCH |
        net::LOAD_IS_DOWNLOAD)) {
     // Avoid pipelining resources that may be streamed for a long time.
     return false;
   }
   return stream_factory_->http_pipelined_host_pool_.IsKeyEligibleForPipelining(
       *http_pipelining_key_.get());
 }
 
 }  // namespace net