Add a field trial for using lower sqlite cache sizes.

chrome/browser/history/history_backend.cc

 // Copyright (c) 2011 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/history/history_backend.h"
 
 #include <list>
 #include <map>
 #include <set>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/time.h"
 #include "chrome/browser/autocomplete/history_url_provider.h"
 #include "chrome/browser/bookmarks/bookmark_service.h"
+#include "chrome/browser/history/history_field_trial.h"
 #include "chrome/browser/history/history_notifications.h"
 #include "chrome/browser/history/history_publisher.h"
 #include "chrome/browser/history/in_memory_history_backend.h"
 #include "chrome/browser/history/page_usage_data.h"
 #include "chrome/browser/history/top_sites.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/cancelable_request.h"
 #include "content/browser/download/download_persistent_store_info.h"
@@ skipping 514 matching lines @@
   ScheduleCommit();
 }
 
 void HistoryBackend::InitImpl(const std::string& languages) {
   DCHECK(!db_.get()) << "Initializing HistoryBackend twice";
   // In the rare case where the db fails to initialize a dialog may get shown
   // the blocks the caller, yet allows other messages through. For this reason
   // we only set db_ to the created database if creation is successful. That
   // way other methods won't do anything as db_ is still NULL.
 
+  HistoryFieldTrial::Activate();
+
   TimeTicks beginning_time = TimeTicks::Now();
 
   // Compute the file names. Note that the index file can be removed when the
   // text db manager is finished being hooked up.
   FilePath history_name = history_dir_.Append(chrome::kHistoryFilename);
   FilePath thumbnail_name = GetThumbnailFileName();
   FilePath archived_name = GetArchivedFileName();
   FilePath tmp_bookmarks_file = history_dir_.Append(
       chrome::kHistoryBookmarksFileName);
 
@@ skipping 649 matching lines @@
       // if (archived_db_.get() &&
       //     expirer_.GetCurrentArchiveTime() - TimeDelta::FromDays(7)) {
     } else {
       // Full text history query.
       QueryHistoryFTS(text_query, options, &request->value);
     }
   }
 
   request->ForwardResult(request->handle(), &request->value);
 
-  UMA_HISTOGRAM_TIMES("History.QueryHistory",
-                      TimeTicks::Now() - beginning_time);
+  UMA_HISTOGRAM_TIMES(
+      "History.QueryHistory" + HistoryFieldTrial::GetGroupSuffix(),
+      TimeTicks::Now() - beginning_time);
 }
 
 // Basic time-based querying of history.
 void HistoryBackend::QueryHistoryBasic(URLDatabase* url_db,
                                        VisitDatabase* visit_db,
                                        const QueryOptions& options,
                                        QueryResults* result) {
   // First get all visits.
   VisitVector visits;
   visit_db->GetVisibleVisitsInRange(options.begin_time, options.end_time,
@@ skipping 1061 matching lines @@
         break;
       }
     }
   }
   UMA_HISTOGRAM_TIMES("History.GetFavIconFromDB",  // historical name
                       TimeTicks::Now() - beginning_time);
   return success;
 }
 
 }  // namespace history