Implement WebPrescientNetworking to trigger preconnect from Blink

chrome/browser/net/url_info.h

Index: chrome/browser/net/url_info.h
diff --git a/chrome/browser/net/url_info.h b/chrome/browser/net/url_info.h
index 54c81591d84c5dd5ef13d9f588c654b30a046675..8d697f144ae4fb06d912e0db5c481ecb79d6e691 100644
--- a/chrome/browser/net/url_info.h
+++ b/chrome/browser/net/url_info.h
@@ -51,6 +51,10 @@ class UrlInfo {
     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.
   };