Field trial removing tiles from NTP if URL is already open - for 1993 clients

chrome/browser/history/top_sites.h

 // Copyright (c) 2012 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.
 
 #ifndef CHROME_BROWSER_HISTORY_TOP_SITES_H_
 #define CHROME_BROWSER_HISTORY_TOP_SITES_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/common/cancelable_request.h"
 #include "chrome/browser/history/history_service.h"
 #include "chrome/browser/history/history_types.h"
+#include "chrome/common/instant_types.h"
 #include "chrome/common/thumbnail_score.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/image/image.h"
 #include "url/gurl.h"
 
 class Profile;
 
 namespace base {
 class FilePath;
 class RefCountedBytes;
@@ skipping 15 matching lines @@
       public content::NotificationObserver {
  public:
   TopSites() {}
 
   // Initializes TopSites.
   static TopSites* Create(Profile* profile, const base::FilePath& db_name);
 
   // Helper method to shuffle MostVisited tiles for A/B testing purposes.
   static void MaybeShuffle(MostVisitedURLList* data);
 
+  // Returns true if this user is part of the Most Visited Tile Placement
+  // experiment group where URLs currently open in the browser are not displayed
+  // on the NTP. Note: the experiment targets only the top-level of sites i.e.
+  // if www.foo.com/bar is open in browser, and www.foo.com is a recommended
+  // URL, www.foo.com will still appear on the next NTP open. The experiment
+  // will not remove a URL if doing so would cause the number of Most Visited
+  // recommendations to drop below eight.
+  static bool IsClientInTabsGroup();

[sky, 2013/07/16 21:15:07]

tabs group? I think this method is poorly named.

[annark1, 2013/07/17 17:45:52]

Done. Renamed to DontShowOpenURLsEnabled

+
+  // Removes URLs already open in browser, for 1993 clients, if part of
+  // experiment described for IsClientInTabsGroup().
+  static void RemoveItemsMatchingOpenTabs(
+      const std::set<std::string>& open_urls,
+      std::vector<InstantMostVisitedItem>* items);
+
+  // Removes URLs already open in browser, for non-1993 clients, if part of
+  // experiment described for IsClientInTabsGroup().
+  static void RemovePageValuesMatchingOpenTabs(
+      const std::set<std::string>& open_urls,
+      base::ListValue* pages_value);
+
   // Sets the given thumbnail for the given URL. Returns true if the thumbnail
   // was updated. False means either the URL wasn't known to us, or we felt
   // that our current thumbnail was superior to the given one. Should be called
   // from the UI thread.
   virtual bool SetPageThumbnail(const GURL& url,
                                 const gfx::Image& thumbnail,
                                 const ThumbnailScore& score) = 0;
 
   // While testing the history system, we want to set the thumbnail to a piece
   // of static memory.
@@ skipping 105 matching lines @@
     // The raw data resource for the thumbnail.
     int thumbnail_id;
     // The best color to highlight the page (should roughly match favicon).
     SkColor color;
   };
  protected:
   virtual ~TopSites() {}
 
  private:
   friend class base::RefCountedThreadSafe<TopSites>;
+
+  // This enum is also defined in histograms.xml. These values represent the
+  // types of actions carried out by the Most Visited Tile Placement experiment.
+  enum NtpTileExperimentActions {
+    NTP_TILE_EXPERIMENT_ACTION_REMOVED_URL = 0,
+    NTP_TILE_EXPERIMENT_ACTION_DID_NOT_REMOVE_URL = 1,
+    NTP_TILE_EXPERIMENT_ACTION_TOO_FEW_URLS_TILES_1_8 = 2,
+    NTP_TILE_EXPERIMENT_ACTION_TOO_FEW_URLS_TILES_1_4 = 3,
+    NTP_TILE_EXPERIMENT_ACTION_NO_URL_TO_FLIP = 4,
+    // The number of Most Visited Tile Placement experiment actions logged.
+    NUM_NTP_TILE_EXPERIMENT_ACTIONS
+  };
+
+  // Helper method to log the actions carried out by the Most Visited Tile
+  // Placement experiment.
+  static void LogInHistogram(NtpTileExperimentActions action);
+
 };
 
 #if defined(OS_ANDROID)
 extern const TopSites::PrepopulatedPage kPrepopulatedPages[1];
 #else
 extern const TopSites::PrepopulatedPage kPrepopulatedPages[2];
 #endif
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_TOP_SITES_H_