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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chrome/browser/history/most_visited_tiles_experiment.h"
      6 
      7 #include "base/metrics/field_trial.h"
      8 #include "base/metrics/histogram.h"
      9 #include "base/strings/string_util.h"
     10 #include "chrome/common/instant_types.h"
     11 
     12 namespace history {
     13 
     14 namespace {
     15 
     16 // Constants for the most visited tile placement field trial.
     17 // ex:
     18 // "OneEightGroup_Flipped" --> Will cause tile 1 and 8 to be flipped.
     19 // "OneEightGroup_NoChange" --> Will not flip anything.
     20 //
     21 // See field trial config (MostVisitedTilePlacement.json) for details.
     22 const char kMostVisitedFieldTrialName[] = "MostVisitedTilePlacement";
     23 // Name of histogram tracking types of actions carried out by the field trial.
     24 const char kMostVisitedExperimentHistogramName[] =
     25     "NewTabPage.MostVisitedTilePlacementExperiment";
     26 const char kOneEightGroupPrefix[] = "OneEight";
     27 const char kOneFourGroupPrefix[] = "OneFour";
     28 const char kFlippedSuffix[] = "Flipped";
     29 const char kDontShowOpenURLsGroupName[] = "DontShowOpenTabs";
     30 // Minimum number of Most Visited suggestions required in order for the Most
     31 // Visited Field Trial to remove a URL already open in the browser.
     32 const size_t kMinUrlSuggestions = 8;
     33 
     34 }  // namespace
     35 
     36 // static
     37 void MostVisitedTilesExperiment::MaybeShuffle(MostVisitedURLList* data) {
     38   const std::string group_name =
     39       base::FieldTrialList::FindFullName(kMostVisitedFieldTrialName);
     40 
     41   // Depending on the study group of the client, we might flip the 1st and 4th
     42   // tiles, or the 1st and 8th, or do nothing.
     43   if (!EndsWith(group_name, kFlippedSuffix, true))
     44     return;
     45 
     46   size_t index_to_flip = 0;
     47   if (StartsWithASCII(group_name, kOneEightGroupPrefix, true)) {
     48     if (data->size() < 8) {
     49       LogInHistogram(NTP_TILE_EXPERIMENT_ACTION_TOO_FEW_URLS_TILES_1_8);
     50       return;
     51     }
     52     index_to_flip = 7;
     53   } else if (StartsWithASCII(group_name, kOneFourGroupPrefix, true)) {
     54     if (data->size() < 4) {
     55       LogInHistogram(NTP_TILE_EXPERIMENT_ACTION_TOO_FEW_URLS_TILES_1_4);
     56       return;
     57     }
     58     index_to_flip = 3;
     59   }
     60   std::swap((*data)[0], (*data)[index_to_flip]);
     61 }
     62 
     63 // static
     64 bool MostVisitedTilesExperiment::IsDontShowOpenURLsEnabled() {
     65   return base::FieldTrialList::FindFullName(kMostVisitedFieldTrialName) ==
     66       kDontShowOpenURLsGroupName;
     67 }
     68 
     69 // static
     70 void MostVisitedTilesExperiment::RemoveItemsMatchingOpenTabs(
     71     const std::set<std::string>& open_urls,
     72     std::vector<InstantMostVisitedItem>* items) {
     73   for (size_t i = 0; i < items->size(); ) {
     74     const std::string& url = (*items)[i].url.spec();
     75     if (ShouldRemoveURL(open_urls, url, items->size()))
     76       items->erase(items->begin() + i);
     77     else
     78       ++i;
     79   }
     80 }
     81 
     82 // static
     83 void MostVisitedTilesExperiment::RemovePageValuesMatchingOpenTabs(
     84     const std::set<std::string>& open_urls,
     85     base::ListValue* pages_value) {
     86   for (size_t i = 0; i < pages_value->GetSize(); ) {
     87     base::DictionaryValue* page_value;
     88     std::string url;
     89     if (pages_value->GetDictionary(i, &page_value) &&
     90         page_value->GetString("url", &url) &&
     91         ShouldRemoveURL(open_urls, url, pages_value->GetSize())) {
     92       pages_value->Remove(*page_value, &i);
     93     } else {
     94       ++i;
     95     }
     96   }
     97 }
     98 
     99 // static
    100 void MostVisitedTilesExperiment::LogInHistogram(
    101     NtpTileExperimentActions action) {
    102   UMA_HISTOGRAM_ENUMERATION(kMostVisitedExperimentHistogramName,
    103                             action,
    104                             NUM_NTP_TILE_EXPERIMENT_ACTIONS);
    105 }
    106 
    107 // static
    108 bool MostVisitedTilesExperiment::ShouldRemoveURL(
    109     const std::set<std::string>& open_urls,
    110     const std::string& url,
    111     const size_t size) {
    112   if (open_urls.count(url) == 0)
    113     return false;
    114 
    115   if (size <= kMinUrlSuggestions) {
    116     LogInHistogram(NTP_TILE_EXPERIMENT_ACTION_DID_NOT_REMOVE_URL);
    117     return false;
    118   }
    119 
    120   LogInHistogram(NTP_TILE_EXPERIMENT_ACTION_REMOVED_URL);
    121   return true;
    122 }
    123 
    124 }  // namespace history
    125