Implement WebPrescientNetworking to trigger preconnect from Blink

chrome/browser/net/url_info.h

 // 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.
 
 // A UrlInfo object is used to store prediction related information about a host
 // port and scheme triplet.  When performing DNS pre-resolution of the host/port
 // pair, its state is monitored as it is resolved.
 // It includes progress, from placement in the Predictor's queue, to resolution
 // by the DNS service as either FOUND or NO_SUCH_NAME.  Each instance may also
 // hold records of previous resolution times, which might later be shown to be
@@ skipping 33 matching lines @@
 
     NO_PREFETCH_MOTIVATION,  // Browser navigation info (not prefetch related).
 
     // The following involve predictive prefetching, triggered by a navigation.
     // The referrinrg_url_ is also set when these are used.
     // TODO(jar): Support STATIC_REFERAL_MOTIVATED API and integration.
     STATIC_REFERAL_MOTIVATED,  // External database suggested this resolution.
     LEARNED_REFERAL_MOTIVATED,  // Prior navigation taught us this resolution.
     SELF_REFERAL_MOTIVATED,  // Guess about need for a second connection.
 
+    MOUSE_DOWN_MOTIVATED,      // Mouse-down link induced preconnect.
+    TAP_UNCONFIRMED_MOTIVATED, // Unconfirmed tap on a link induced preconnect.
+    TAP_DOWN_MOTIVATED,        // Tap-down link induced preconnect.
+
     MAX_MOTIVATED  // Beyond all enums, for use in histogram bounding.
   };
 
   enum DnsProcessingState {
       // When processed by our prefetching system, the states are:
       PENDING,       // Constructor has completed.
       QUEUED,        // In name queue but not yet being resolved.
       ASSIGNED,      // Being resolved (or being reset to earlier state)
       ASSIGNED_BUT_MARKED,  // Needs to be deleted as soon as it's resolved.
       FOUND,         // DNS resolution completed.
@@ skipping 115 matching lines @@
   GURL referring_url_;
 
   // We put these objects into a std::map, and hence we
   // need some "evil" constructors.
   // DISALLOW_COPY_AND_ASSIGN(UrlInfo);
 };
 
 }  // namespace chrome_browser_net
 
 #endif  // CHROME_BROWSER_NET_URL_INFO_H_