Adaptively identify URL subresources and pre-resolve hosts via DNS

Use the HTTP "referer" header to identify subresources used during a
page load.  Store that info, and use it when next visiting the referenced
hosts to pre-resolve the (probably) needed subresources.

This set of changes will surely evolve as we see how it plays out
on broader distribution (via histogram measurments), but this should be
the foundation of the change.

In design specs, this was previously referred to as "adaptive correlated
DNS prefetching."

r=mbelshe


Review URL: http://codereview.chromium.org/9168

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@4929 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 4 insertions, 1 deletions

diff --git a/net/http/http_transaction_winhttp.cc b/net/http/http_transaction_winhttp.cc
index a1eb3f8..bb5f610 100644
--- a/net/http/http_transaction_winhttp.cc
+++ b/net/http/http_transaction_winhttp.cc
@@ -702,6 +702,7 @@ void HttpTransactionWinHttp::StatusCallback(HINTERNET handle,
       if (API_SEND_REQUEST == result->dwResult &&
           ERROR_WINHTTP_NAME_NOT_RESOLVED == result->dwError)
         DidFinishDnsResolutionWithStatus(false,
+                                         GURL(),  // null referrer URL.
                                          reinterpret_cast<void*>(context));
       break;
     }
@@ -725,7 +726,9 @@ void HttpTransactionWinHttp::StatusCallback(HINTERNET handle,
     }
     // Successfully found the IP address of the server.
     case WINHTTP_CALLBACK_STATUS_NAME_RESOLVED:
-      DidFinishDnsResolutionWithStatus(true, reinterpret_cast<void*>(context));
+      DidFinishDnsResolutionWithStatus(true,
+                                       GURL(),  // null referer URL.
+                                       reinterpret_cast<void*>(context));
       break;
   }
 }