predictors: Put manifests for ResourcePrefetchPredictor behind a flag.

chrome/browser/predictors/resource_prefetch_predictor.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/predictors/resource_prefetch_predictor.h"
 
 #include <map>
 #include <set>
 #include <utility>
 
@@ skipping 1449 matching lines @@
   }
 }
 
 void ResourcePrefetchPredictor::OnManifestFetched(
     const std::string& host,
     const precache::PrecacheManifest& manifest) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   if (initialization_state_ != INITIALIZED)
     return;
 
-  if (host.length() > ResourcePrefetchPredictorTables::kMaxStringLength ||
+  if (!config_.is_manifests_enabled ||
+      host.length() > ResourcePrefetchPredictorTables::kMaxStringLength ||
       static_cast<uint32_t>(manifest.ByteSize()) > kMaxManifestByteSize) {
     return;
   }
 
   auto cache_entry = manifest_table_cache_->find(host);
   if (cache_entry == manifest_table_cache_->end()) {
     if (manifest_table_cache_->size() >= config_.max_hosts_to_track)
       RemoveOldestEntryInManifestDataMap(manifest_table_cache_.get());
     cache_entry =
         manifest_table_cache_->insert(std::make_pair(host, manifest)).first;
@@ skipping 30 matching lines @@
 TestObserver::~TestObserver() {
   predictor_->SetObserverForTesting(nullptr);
 }
 
 TestObserver::TestObserver(ResourcePrefetchPredictor* predictor)
     : predictor_(predictor) {
   predictor_->SetObserverForTesting(this);
 }
 
 }  // namespace predictors