[Spellcheck] Add UMA stat for SpellingService

chrome/browser/spellchecker/spellcheck_host_metrics.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/spellchecker/spellcheck_host_metrics.h"
 
 #include "base/md5.h"
 #include "base/metrics/histogram.h"
 
 SpellCheckHostMetrics::SpellCheckHostMetrics()
@@ skipping 122 matching lines @@
     UMA_HISTOGRAM_COUNTS("SpellCheck.UniqueWords", checked_word_hashes_.size());
     last_unique_word_count_ = checked_word_hashes_.size();
   }
 
   if (suggestion_show_count_ != last_suggestion_show_count_) {
     DCHECK(suggestion_show_count_ > last_suggestion_show_count_);
     UMA_HISTOGRAM_COUNTS("SpellCheck.ShownSuggestions", suggestion_show_count_);
     last_suggestion_show_count_ = suggestion_show_count_;
   }
 }
+
+void SpellCheckHostMetrics::RecordSpellingServiceStats(bool enabled) {
+  UMA_HISTOGRAM_BOOLEAN("SpellCheck.SpellingService.Enabled", enabled);
+}