Reland 54771 (and 54795) To enable TCP Preconnection by default...

chrome/browser/net/predictor.h

Index: chrome/browser/net/predictor.h
===================================================================
--- chrome/browser/net/predictor.h	(revision 55024)
+++ chrome/browser/net/predictor.h	(working copy)
@@ -83,8 +83,11 @@
   void Resolve(const GURL& url,
                UrlInfo::ResolutionMotivation motivation);
 
-  // Instigate pre-connection to any URLs we predict will be needed after this
-  // navigation (typically more-embedded resources on a page).
+  // Instigate pre-connection to any URLs, or pre-resolution of related host,
+  // that we predict will be needed after this navigation (typically
+  // more-embedded resources on a page).  This method will actually post a task
+  // to do the actual work, so as not to jump ahead of the frame navigation that
+  // instigated this activity.
   void PredictFrameSubresources(const GURL& url);
 
   // Record details of a navigation so that we can preresolve the host name
@@ -138,8 +141,6 @@
   FRIEND_TEST_ALL_PREFIXES(PredictorTest, PriorityQueueReorderTest);
   friend class WaitForResolutionHelper;  // For testing.
 
-  ~Predictor();
-
   class LookupRequest;
 
   // A simple priority queue for handling host names.
@@ -174,6 +175,13 @@
   // in a Referrer instance, which is a value in this map.
   typedef std::map<GURL, Referrer> Referrers;
 
+  ~Predictor();
+
+  // Perform actual resolution or preconnection to subresources now.  This is
+  // an internal worker method that is reached via a post task from
+  // PredictFrameSubresources().
+  void PrepareFrameSubresources(const GURL& url);
+
   // Only for testing. Returns true if hostname has been successfully resolved
   // (name found).
   bool WasFound(const GURL& url) const {