Add the UMA recording recall of URLRequests preconnected.

chrome/browser/net/connect_interceptor.cc

 // Copyright (c) 2011 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/connect_interceptor.h"
 
+#include "base/metrics/histogram.h"
 #include "chrome/browser/net/predictor.h"
 #include "net/base/load_flags.h"
 #include "net/url_request/url_request.h"
 
 namespace chrome_browser_net {
 
 // We don't bother learning to preconnect via a GET if the original URL
 // navigation was so long ago, that a preconnection would have been dropped
 // anyway.  We believe most servers will drop the connection in 10 seconds, so
 // we currently estimate this time-till-drop at 10 seconds.
 // TODO(jar): We should do a persistent field trial to validate/optimize this.
 static const int kMaxUnusedSocketLifetimeSecondsWithoutAGet = 10;
 
 ConnectInterceptor::ConnectInterceptor(Predictor* predictor)
     : timed_cache_(base::TimeDelta::FromSeconds(
           kMaxUnusedSocketLifetimeSecondsWithoutAGet)),
+      recent_preconnects_(base::TimeDelta::FromSeconds(
+          kMaxUnusedSocketLifetimeSecondsWithoutAGet)),
       predictor_(predictor) {
   DCHECK(predictor);
 }
 
 ConnectInterceptor::~ConnectInterceptor() {
 }
 
 void ConnectInterceptor::WitnessURLRequest(net::URLRequest* request) const {
   GURL request_scheme_host(Predictor::CanonicalizeUrl(request->url()));
   if (request_scheme_host == GURL::EmptyGURL())
@@ skipping 37 matching lines @@
     if (referring_scheme_host == request_scheme_host) {
       // We've already made any/all predictions when we navigated to the
       // referring host, so we can bail out here.
       // We don't update the RecentlySeen() time because any preconnections
       // need to be made at the first navigation (i.e., when referer was loaded)
       // and wouldn't have waited for this current request navigation.
       return;
     }
   }
   timed_cache_.SetRecentlySeen(request_scheme_host);
+  UMA_HISTOGRAM_BOOLEAN(
+      "Net.PreconnectedNavigation",
+      recent_preconnects_.WasRecentlySeen(request_scheme_host));
 
   // Subresources for main frames usually get predicted when we detected the
   // main frame request - way back in RenderViewHost::Navigate.  So only handle
   // predictions now for subresources or for redirected hosts.
   if ((request->load_flags() & net::LOAD_SUB_FRAME) || redirected_host)
     predictor_->PredictFrameSubresources(request_scheme_host,
                                          request->first_party_for_cookies());
   return;
 }
 
+void ConnectInterceptor::WitnessPreconnect(const GURL& url) {
+  GURL request_scheme_host(Predictor::CanonicalizeUrl(url));
+  recent_preconnects_.SetRecentlySeen(request_scheme_host);

[mmenke, 2013/05/22 17:58:43]

I think this could actually all be done in the predictor more simply, since
|this| owns it.

[kouhei (in TOK), 2013/05/23 07:31:13]

I tried moving the logic to Predictor. TimedCache is also moved out from
ConnectInterceptor so that I can use it from Predictor too.

+}
+
 ConnectInterceptor::TimedCache::TimedCache(const base::TimeDelta& max_duration)
     : mru_cache_(UrlMruTimedCache::NO_AUTO_EVICT),
       max_duration_(max_duration) {
 }
 
 // Make Clang compilation happy with explicit destructor.
 ConnectInterceptor::TimedCache::~TimedCache() {}
 
 bool ConnectInterceptor::TimedCache::WasRecentlySeen(const GURL& url) const {
   DCHECK_EQ(url.GetWithEmptyPath(), url);
   // Evict any overly old entries.
   base::TimeTicks now = base::TimeTicks::Now();
   UrlMruTimedCache::reverse_iterator eldest = mru_cache_.rbegin();
   while (!mru_cache_.empty()) {
     DCHECK(eldest == mru_cache_.rbegin());
     if (now - eldest->second < max_duration_)
       break;
     eldest = mru_cache_.Erase(eldest);
   }
   return mru_cache_.end() != mru_cache_.Peek(url);
 }
 
 void ConnectInterceptor::TimedCache::SetRecentlySeen(const GURL& url) const {
   DCHECK_EQ(url.GetWithEmptyPath(), url);
   mru_cache_.Put(url, base::TimeTicks::Now());
 }
 
 }  // namespace chrome_browser_net