predictors: Mark before_first_contentful_paint for resources fetched before fcp.

chrome/browser/predictors/resource_prefetch_predictor.proto

 // Copyright 2016 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.
 
 // Protocol buffers used for storing in SQLite.
 // CAUTION: When any change is done here, bump kDatabaseVersion in
 //          resource_prefetch_predictor_tables.h.
 
 syntax = "proto2";
 
@@ skipping 39 matching lines @@
 
   optional string resource_url = 1;
   optional ResourceType resource_type = 2;
   optional uint32 number_of_hits = 3;
   optional uint32 number_of_misses = 4;
   optional uint32 consecutive_misses = 5;
   optional double average_position = 6;
   optional Priority priority = 7;
   optional bool has_validators = 8;
   optional bool always_revalidate = 9;
+  optional bool before_first_contentful_paint = 10;
 }
 
 // Represents a collection of subresources associated with URL or host.
 message PrefetchData {
   // Main frame URL of host.
   optional string primary_key = 1;
   optional uint64 last_visit_time = 2;
   repeated ResourceData resources = 3;
 }
 
@@ skipping 24 matching lines @@
   optional bool always_access_network = 6;
   optional bool accessed_network = 7;
 }
 
 // Collection of origins accessed from a host.
 message OriginData {
   optional string host = 1;
   optional uint64 last_visit_time = 2;
   repeated OriginStat origins = 3;
 }