predictors: Don't call IsUrlPrefetchable twice.

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 566 matching lines @@
     std::unique_ptr<ResourcePrefetcher::PrefetcherStats> stats) {
   if (observer_)
     observer_->OnPrefetchingFinished(main_frame_url);
 
   if (stats_collector_)
     stats_collector_->RecordPrefetcherStats(std::move(stats));
 }
 
 bool ResourcePrefetchPredictor::IsUrlPrefetchable(
     const GURL& main_frame_url) const {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  if (initialization_state_ != INITIALIZED)
-    return false;
-
   return GetPrefetchData(main_frame_url, nullptr);
 }
 
 bool ResourcePrefetchPredictor::IsResourcePrefetchable(
     const ResourceData& resource) const {
   float confidence = static_cast<float>(resource.number_of_hits()) /
                      (resource.number_of_hits() + resource.number_of_misses());
   return confidence >= config_.min_resource_confidence_to_trigger_prefetch &&
          resource.number_of_hits() >=
              config_.min_resource_hits_to_trigger_prefetch;
@@ skipping 135 matching lines @@
     history_service->TopHosts(
         kNumSampleHosts,
         base::Bind(&ResourcePrefetchPredictor::ReportDatabaseReadiness,
                    AsWeakPtr()));
   }
 }
 
 bool ResourcePrefetchPredictor::GetPrefetchData(
     const GURL& main_frame_url,
     ResourcePrefetchPredictor::Prediction* prediction) const {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (initialization_state_ != INITIALIZED)
+    return false;
+
   std::vector<GURL>* urls =
       prediction ? &prediction->subresource_urls : nullptr;
   DCHECK(!urls || urls->empty());
 
   // Fetch resources using URL-keyed data first.
   std::string redirect_endpoint;
   const std::string& main_frame_url_spec = main_frame_url.spec();
   if (config_.is_url_learning_enabled &&
       GetRedirectEndpoint(main_frame_url_spec, *url_redirect_data_,
                           &redirect_endpoint) &&
@@ skipping 634 matching lines @@
   if (!history_service)
     return;
   DCHECK(!history_service_observer_.IsObserving(history_service));
   history_service_observer_.Add(history_service);
   if (history_service->BackendLoaded()) {
     // HistoryService is already loaded. Continue with Initialization.
     OnHistoryAndCacheLoaded();
   }
 }
 
-void ResourcePrefetchPredictor::StartPrefetching(const GURL& url) {
+void ResourcePrefetchPredictor::StartPrefetching(
+    const GURL& url,
+    const ResourcePrefetchPredictor::Prediction& prediction) {
   TRACE_EVENT1("browser", "ResourcePrefetchPredictor::StartPrefetching", "url",
                url.spec());
   if (!prefetch_manager_.get())  // Not enabled.
     return;
 
-  ResourcePrefetchPredictor::Prediction prediction;
-  bool has_data = GetPrefetchData(url, &prediction);
-  DCHECK(has_data);
-
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
       base::BindOnce(&ResourcePrefetcherManager::MaybeAddPrefetch,
                      prefetch_manager_, url, prediction.subresource_urls));
 
   if (observer_)
     observer_->OnPrefetchingStarted(url);
 }
 
 void ResourcePrefetchPredictor::StopPrefetching(const GURL& url) {
@@ skipping 17 matching lines @@
 TestObserver::~TestObserver() {
   predictor_->SetObserverForTesting(nullptr);
 }
 
 TestObserver::TestObserver(ResourcePrefetchPredictor* predictor)
     : predictor_(predictor) {
   predictor_->SetObserverForTesting(this);
 }
 
 }  // namespace predictors