add UMA for no. of pages with no distilled data

components/dom_distiller/core/viewer.cc

 // Copyright 2014 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/dom_distiller/core/viewer.h"
 
 #include <string>
 #include <vector>
 
 #include "base/json/json_writer.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
 #include "components/dom_distiller/core/distilled_page_prefs.h"
 #include "components/dom_distiller/core/dom_distiller_service.h"
 #include "components/dom_distiller/core/proto/distilled_article.pb.h"
 #include "components/dom_distiller/core/proto/distilled_page.pb.h"
 #include "components/dom_distiller/core/task_tracker.h"
 #include "components/dom_distiller/core/url_constants.h"
 #include "components/dom_distiller/core/url_utils.h"
 #include "grit/components_resources.h"
 #include "grit/components_strings.h"
@@ skipping 66 matching lines @@
   }
   return kSansSerifCssClass;
 }
 
 void EnsureNonEmptyTitleAndContent(std::string* title, std::string* content) {
   if (title->empty())
     *title = l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_TITLE);
   if (content->empty()) {
     *content = l10n_util::GetStringUTF8(
         IDS_DOM_DISTILLER_VIEWER_NO_DATA_CONTENT);
+    UMA_HISTOGRAM_COUNTS("DomDistiller.Statistics.NoDistilledDataCount", 1);

[nyquist, 2014/09/26 21:52:54]

It doesn't feel right to do this as a histogram to me, given the number is hard
coded. If you  do a histogram, how about counting 0 on the outside and 1 on the
inside? And if you do that, you might want to use a boolean instead? See
UMA_HISTOGRAM_BOOLEAN. I think that makes sense

If you want to do a count in general, you could do that too, but then you would
have to compare it to some other count. Actions are sadly defined in //content
though:
https://chromium.googlesource.com/chromium/src.git/+/master/content/public/br...

Is that why you chose histogram?

Anyway: I vote for boolean about empty and non-empty histogram. That should give
us all the numbers we need.

[kuan, 2014/09/26 22:46:55]

Done.

   }
 }
 
 std::string ReplaceHtmlTemplateValues(
     const std::string& title,
     const std::string& content,
     const std::string& loading_indicator_class,
     const std::string& original_url,
     const DistilledPagePrefs::Theme theme,
     const DistilledPagePrefs::FontFamily font_family) {
@@ skipping 145 matching lines @@
 }
 
 const std::string GetDistilledPageFontFamilyJs(
     DistilledPagePrefs::FontFamily font_family) {
   return "useFontFamily('" + GetJsFontFamily(font_family) + "');";
 }
 
 }  // namespace viewer
 
 }  // namespace dom_distiller