Prefer opening PDF downloads in the browser.

chrome/browser/download/download_stats.cc

 // Copyright 2013 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/download/download_stats.h"
 
 #include "base/metrics/histogram.h"
 
 void RecordDownloadShelfClose(int size, int in_progress, bool autoclose) {
   static const int kMaxShelfSize = 16;
@@ skipping 19 matching lines @@
   UMA_HISTOGRAM_ENUMERATION(
       "Download.SourcesChrome", source, CHROME_DOWNLOAD_SOURCE_LAST_ENTRY);
 }
 
 void RecordOpenedDangerousConfirmDialog(
     content::DownloadDangerType danger_type) {
   UMA_HISTOGRAM_ENUMERATION("Download.ShowDangerousDownloadConfirmationPrompt",
                             danger_type,
                             content::DOWNLOAD_DANGER_TYPE_MAX);
 }
+
+void RecordDownloadOpenMethod(ChromeDownloadOpenMethod open_method) {
+  UMA_HISTOGRAM_ENUMERATION("Download.OpenMethod",
+                            open_method,
+                            DOWNLOAD_OPEN_METHOD_LAST_ENTRY);
+}