predictors: Remove resources marked as unused.

chrome/browser/predictors/resource_prefetch_predictor_unittest.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 <iostream>
 #include <memory>
 #include <utility>
 
@@ skipping 1163 matching lines @@
     return m.ByteSize() == manifest_size;
   };
   EXPECT_CALL(
       *mock_tables_.get(),
       UpdateManifestData("google.com",
                          testing::AllOf(manifest, testing::Truly(match_size))));
 
   predictor_->OnManifestFetched("google.com", manifest_with_unknown_fields);
 }
 
+TEST_F(ResourcePrefetchPredictorTest, ManifestUnusedRemoved) {
+  const std::string& script_url = "http://cdn.google.com/script.js";
+  const std::string& style_url = "http://cdn.google.com/style.css";
+  PrefetchData google = CreatePrefetchData("www.google.com");
+  InitializeResourceData(google.add_resources(), script_url,
+                         content::RESOURCE_TYPE_SCRIPT, 10, 0, 1, 2.1,
+                         net::MEDIUM, false, false);
+  InitializeResourceData(google.add_resources(), style_url,
+                         content::RESOURCE_TYPE_SCRIPT, 10, 0, 1, 2.1,
+                         net::MEDIUM, false, false);
+  predictor_->host_table_cache_->insert({google.primary_key(), google});
+
+  precache::PrecacheManifest manifest = CreateManifestData(1);
+  InitializePrecacheResource(manifest.add_resource(), script_url, 0.9);
+  InitializePrecacheResource(manifest.add_resource(), style_url, 0.75);
+  InitializeExperiment(&manifest, internal::kUnusedRemovedExperiment,
+                       {true, false});
+
+  // style_url should be removed.
+  google.mutable_resources()->RemoveLast();
+  EXPECT_CALL(*mock_tables_.get(),
+              UpdateResourceData(google, PREFETCH_KEY_TYPE_HOST));
+  EXPECT_CALL(*mock_tables_.get(), UpdateManifestData("google.com", manifest));
+
+  predictor_->OnManifestFetched("google.com", manifest);
+}
+
 TEST_F(ResourcePrefetchPredictorTest, DeleteUrls) {
   // Add some dummy entries to cache.
   predictor_->url_table_cache_->insert(
       std::make_pair("http://www.google.com/page1.html",
                      CreatePrefetchData("http://www.google.com/page1.html")));
   predictor_->url_table_cache_->insert(
       std::make_pair("http://www.google.com/page2.html",
                      CreatePrefetchData("http://www.google.com/page2.html")));
   predictor_->url_table_cache_->insert(std::make_pair(
       "http://www.yahoo.com/", CreatePrefetchData("http://www.yahoo.com/")));
@@ skipping 791 matching lines @@
   predictor_->host_table_cache_->insert(
       std::make_pair(google.primary_key(), google));
 
   predictor_->StartPrefetching(GURL(main_frame_url), PrefetchOrigin::EXTERNAL);
   predictor_->StopPrefetching(GURL(main_frame_url));
   histogram_tester_->ExpectTotalCount(
       internal::kResourcePrefetchPredictorPrefetchingDurationHistogram, 1);
 }
 
 }  // namespace predictors