Count external PDF viewer usage in print preview.

chrome/browser/ui/webui/print_preview/print_preview_handler.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 "chrome/browser/ui/webui/print_preview/print_preview_handler.h"
 
 #include <ctype.h>
 
 #include <map>
 #include <string>
@@ skipping 100 matching lines @@
   PORTRAIT,
   COLOR,
   BLACK_AND_WHITE,
   COLLATE,
   SIMPLEX,
   DUPLEX,
   TOTAL,
   HEADERS_AND_FOOTERS,
   CSS_BACKGROUND,
   SELECTION_ONLY,
+  EXTERNAL_PDF_PREVIEW,
   PRINT_SETTINGS_BUCKET_BOUNDARY
 };
 
 enum UiBucketGroups {
   DESTINATION_SEARCH,
   GCP_PROMO,
   UI_BUCKET_GROUP_BOUNDARY
 };
 
 enum PrintDestinationBuckets {
@@ skipping 123 matching lines @@
   if (settings.GetBoolean(printing::kSettingShouldPrintBackgrounds,
                           &css_background) && css_background) {
     ReportPrintSettingHistogram(CSS_BACKGROUND);
   }
 
   bool selection_only = false;
   if (settings.GetBoolean(printing::kSettingShouldPrintSelectionOnly,
                           &selection_only) && selection_only) {
     ReportPrintSettingHistogram(SELECTION_ONLY);
   }
+
+  bool external_preview = false;
+  if (settings.GetBoolean(printing::kSettingOpenPDFInPreview,
+                          &external_preview) && external_preview) {
+    ReportPrintSettingHistogram(EXTERNAL_PDF_PREVIEW);
+  }
 }
 
 // Callback that stores a PDF file on disk.
 void PrintToPdfCallback(printing::Metafile* metafile,
                         const base::FilePath& path) {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   metafile->SaveTo(path);
   // |metafile| must be deleted on the UI thread.
   BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, metafile);
 }
@@ skipping 1333 matching lines @@
     reconcilor_ = AccountReconcilorFactory::GetForProfile(profile);
     if (reconcilor_)
       reconcilor_->AddMergeSessionObserver(this);
   }
 }
 
 void PrintPreviewHandler::UnregisterForMergeSession() {
   if (reconcilor_)
     reconcilor_->RemoveMergeSessionObserver(this);
 }