Add metrics for calculating precision/recall of link navigation pre-connect triggers.

chrome/browser/net/predictor.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 "chrome/browser/net/predictor.h"
 
 #include <algorithm>
 #include <cmath>
 #include <set>
 #include <sstream>
@@ skipping 826 matching lines @@
     BrowserThread::PostTask(
         BrowserThread::IO,
         FROM_HERE,
         base::Bind(&Predictor::PreconnectUrlOnIOThread,
                    base::Unretained(this), url, first_party_for_cookies,
                    motivation, count));
   }
 }
 
 void Predictor::PreconnectUrlOnIOThread(
     const GURL& url, const GURL& first_party_for_cookies,

[jar (doing other things), 2013/06/10 03:17:16]

nit: one arg per line for definitions and declarations.

If you clean up this line, you might want to do the same to other instances in
this file.

I think the coding style evolved (in a positive direction), and at a minimum you
should clean up any method/function that you piddle with.

[kouhei (in TOK), 2013/06/10 23:24:05]

Ack.

[kouhei (in TOK), 2013/06/14 16:49:42]

I would like to address this in other CL.

     UrlInfo::ResolutionMotivation motivation, int count) {
   GURL canonical_url(CanonicalizeUrl(url));
+
+  UMA_HISTOGRAM_BOOLEAN(
+      "Net.PreconnectsUnique",
+      recent_preconnects_.WasRecentlySeen(canonical_url));

[jar (doing other things), 2013/06/10 03:17:16]

Why is this an interesting stat?

I expect that connection pooling will disregard any extraneous or repeated
preconnect requests, so why do we care if we request preconnects more than once
(in a short(?) period of time?

   recent_preconnects_.SetRecentlySeen(canonical_url);
 
   PreconnectOnIOThread(url,
                        first_party_for_cookies,
                        motivation,
                        count,
                        url_request_context_getter_.get());
 }
 
 void Predictor::RecordPreconnectNavigationStats(const GURL& url) {
@@ skipping 367 matching lines @@
     IOThread* io_thread,
     net::URLRequestContextGetter* getter) {
   // Empty function for unittests.
 }
 
 void SimplePredictor::ShutdownOnUIThread(PrefService* user_prefs) {
   SetShutdown(true);
 }
 
 }  // namespace chrome_browser_net