[Downloads] Remove unmapped histograms.

components/history/core/browser/download_database.cc

 // 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.
 
 #include "components/history/core/browser/download_database.h"
 
 #include <inttypes.h>
 
 #include <limits>
 #include <memory>
@@ skipping 11 matching lines @@
 #include "build/build_config.h"
 #include "components/history/core/browser/download_constants.h"
 #include "components/history/core/browser/download_row.h"
 #include "components/history/core/browser/history_types.h"
 #include "sql/statement.h"
 
 namespace history {
 
 namespace {
 
-// Reason for dropping a particular record.
+// Reason for dropping a particular record. Used for UMA.
 enum DroppedReason {
   DROPPED_REASON_BAD_STATE = 0,
   DROPPED_REASON_BAD_DANGER_TYPE = 1,
   DROPPED_REASON_BAD_ID = 2,
   DROPPED_REASON_DUPLICATE_ID = 3,
   DROPPED_REASON_MAX
 };
 
 #if defined(OS_POSIX)
 
@@ skipping 574 matching lines @@
       return false;
     }
   }
 
   {
     sql::Statement count_urls(GetDB().GetCachedStatement(SQL_FROM_HERE,
         "SELECT count(*) FROM downloads_url_chains WHERE id=?"));
     count_urls.BindInt(0, info.id);
     if (count_urls.Step()) {
       bool corrupt_urls = count_urls.ColumnInt(0) > 0;
-      UMA_HISTOGRAM_BOOLEAN("Download.DatabaseCorruptUrls", corrupt_urls);
       if (corrupt_urls) {
         // There should not be any URLs in downloads_url_chains for this
         // info.id.  If there are, we don't want them to interfere with
         // inserting the correct URLs, so just remove them.
         RemoveDownloadURLs(info.id);
       }
     }
   }
 
   sql::Statement statement_insert_chain(
@@ skipping 43 matching lines @@
 size_t DownloadDatabase::CountDownloads() {
   EnsureInProgressEntriesCleanedUp();
 
   sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
       "SELECT count(*) from downloads"));
   statement.Step();
   return statement.ColumnInt(0);
 }
 
 }  // namespace history