Add some basic success/failure UMA logging for autofill.

chrome/browser/autofill/autofill_metrics.cc

 // Copyright (c) 2010 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/autofill/autofill_metrics.h"
 
 #include "base/metrics/histogram.h"
 
 namespace autofill_metrics {
 
 void LogServerQueryMetric(ServerQueryMetricType type) {
   DCHECK(type < NUM_SERVER_QUERY_METRICS);
 
   UMA_HISTOGRAM_ENUMERATION("AutoFill.ServerQueryResponse", type,
                             NUM_SERVER_QUERY_METRICS);
 }
 
+void LogQualityMetric(QualityMetricType type) {
+  DCHECK(type < NUM_QUALITY_METRICS);
+
+  UMA_HISTOGRAM_ENUMERATION("AutoFill.Quality", type,
+                            NUM_QUALITY_METRICS);
+}
+
 }  // namespace autofill_metrics