Support predictive redundant preconnection

When a page loads additional content via secondary
connections from its own domain, this CL should
learn from those connections, and reserve additional
connections during the primary connection.

r=mbelshe@chromium.org
bug=72666
Review URL: http://codereview.chromium.org/6487019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@74679 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 7 insertions, 10 deletions

diff --git a/chrome/browser/net/connect_interceptor.cc b/chrome/browser/net/connect_interceptor.cc
index 3809da2..56ecbc9 100644
--- a/chrome/browser/net/connect_interceptor.cc
+++ b/chrome/browser/net/connect_interceptor.cc
@@ -49,19 +49,15 @@ net::URLRequestJob* ConnectInterceptor::MaybeIntercept(
     }
   } else {
     GURL referring_scheme_host = GURL(request->referrer()).GetWithEmptyPath();
-    if (referring_scheme_host == request_scheme_host) {
-      // There is nothing to learn about preconnections when the referrer is
-      // already the site needed in the request URL.  Similarly, we've already
-      // made any/all predictions when we navigated to the referring host, so we
-      // can bail out here. This will also avoid useless boosting of the number
-      // of times we navigated to this site, which was already accounted for by
-      // the navigation to the referrering_url.
-      return NULL;
-    }
     bool is_subresource = !(request->load_flags() & net::LOAD_MAIN_FRAME);
     // Learn about our referring URL, for use in the future.
     if (is_subresource)
       LearnFromNavigation(referring_scheme_host, request_scheme_host);
+    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.
+      return NULL;
+    }
   }
 
   // Subresources for main frames usually get predicted when we detected the
diff --git a/chrome/browser/net/predictor.cc b/chrome/browser/net/predictor.cc
index 46dcf1f..327d709 100644
--- a/chrome/browser/net/predictor.cc
+++ b/chrome/browser/net/predictor.cc
@@ -133,7 +133,6 @@ void Predictor::LearnFromNavigation(const GURL& referring_url,
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   DCHECK(referring_url == referring_url.GetWithEmptyPath());
   DCHECK(target_url == target_url.GetWithEmptyPath());
-  DCHECK(target_url != referring_url);
   if (referring_url.has_host()) {
     referrers_[referring_url].SuggestHost(target_url);
   }
@@ -258,6 +257,8 @@ void Predictor::PrepareFrameSubresources(const GURL& url) {
       evalution = PRECONNECTION;
       future_url->second.IncrementPreconnectionCount();
       int count = static_cast<int>(std::ceil(connection_expectation));
+      if (url.host() == future_url->first.host())
+        ++count;
       Preconnect::PreconnectOnIOThread(future_url->first, motivation, count);
     } else if (connection_expectation > kDNSPreresolutionWorthyExpectedValue) {
       evalution = PRERESOLUTION;