Adding UMA metric to record the type of suggestion displayed on the NTP's Most Visited section.

chrome/browser/ui/webui/ntp/ntp_user_data_logger.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/ui/webui/ntp/ntp_user_data_logger.h"
 
 #include "base/metrics/histogram.h"
 #include "chrome/browser/search/search.h"
 #include "chrome/common/search_urls.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/navigation_details.h"
 
+namespace {
+
+// Used to track if suggestions were issued by the client or the server.
+enum SuggestionsType {
+  CLIENT_SIDE = 0,
+  SERVER_SIDE = 1,
+  SUGGESTIONS_TYPE_COUNT = 2
+};
+
+}  // namespace
+
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(NTPUserDataLogger);
 
 NTPUserDataLogger::~NTPUserDataLogger() {}
 
 void NTPUserDataLogger::EmitThumbnailErrorRate() {

[Mathieu, 2013/11/22 19:58:19]

update function name to indicate expanded role

[beaudoin, 2013/11/22 20:09:35]

Renamed and called independently.

Done.

   DCHECK_LE(number_of_thumbnail_errors_, number_of_thumbnail_attempts_);
   if (number_of_thumbnail_attempts_ != 0) {
     UMA_HISTOGRAM_PERCENTAGE(
       "NewTabPage.ThumbnailErrorRate",
       GetPercentError(number_of_thumbnail_errors_,
                       number_of_thumbnail_attempts_));
   }
   DCHECK_LE(number_of_fallback_thumbnails_used_,
             number_of_fallback_thumbnails_requested_);
   if (number_of_fallback_thumbnails_requested_ != 0) {
     UMA_HISTOGRAM_PERCENTAGE(
         "NewTabPage.ThumbnailFallbackRate",
         GetPercentError(number_of_fallback_thumbnails_used_,
                         number_of_fallback_thumbnails_requested_));
   }
+  UMA_HISTOGRAM_ENUMERATION(
+      "NewTabPage.SuggestionsType",
+      server_side_suggestions_ ? SERVER_SIDE : CLIENT_SIDE,
+      SUGGESTIONS_TYPE_COUNT);
   number_of_thumbnail_attempts_ = 0;
   number_of_thumbnail_errors_ = 0;
   number_of_fallback_thumbnails_requested_ = 0;
   number_of_fallback_thumbnails_used_ = 0;
+  server_side_suggestions_ = false;
 }
 
 void NTPUserDataLogger::EmitMouseoverCount() {
   UMA_HISTOGRAM_COUNTS("NewTabPage.NumberOfMouseOvers", number_of_mouseovers_);
   number_of_mouseovers_ = 0;
 }
 
 void NTPUserDataLogger::LogEvent(NTPLoggingEventType event) {
   switch (event) {
     case NTP_MOUSEOVER:
       number_of_mouseovers_++;
       break;
     case NTP_THUMBNAIL_ATTEMPT:
       number_of_thumbnail_attempts_++;
       break;
     case NTP_THUMBNAIL_ERROR:
       number_of_thumbnail_errors_++;
       break;
     case NTP_FALLBACK_THUMBNAIL_REQUESTED:
       number_of_fallback_thumbnails_requested_++;
       break;
     case NTP_FALLBACK_THUMBNAIL_USED:
       number_of_fallback_thumbnails_used_++;
       break;
+    case NTP_SERVER_SIDE_SUGGESTION:
+      server_side_suggestions_ = true;
+      break;
     default:
       NOTREACHED();
   }
 }
 
 // content::WebContentsObserver override
 void NTPUserDataLogger::NavigationEntryCommitted(
     const content::LoadCommittedDetails& load_details) {
   if (!load_details.previous_url.is_valid())
     return;
 
   if (search::MatchesOriginAndPath(ntp_url_, load_details.previous_url)) {
     EmitMouseoverCount();
     // Only log thumbnail error rates for Instant NTP pages, as we do not have
     // this data for non-Instant NTPs.
     if (ntp_url_ != GURL(chrome::kChromeUINewTabURL))
       EmitThumbnailErrorRate();
   }
 }
 
 NTPUserDataLogger::NTPUserDataLogger(content::WebContents* contents)
     : content::WebContentsObserver(contents),
       number_of_mouseovers_(0),
       number_of_thumbnail_attempts_(0),
       number_of_thumbnail_errors_(0),
       number_of_fallback_thumbnails_requested_(0),
-      number_of_fallback_thumbnails_used_(0) {
+      number_of_fallback_thumbnails_used_(0),
+      server_side_suggestions_(false) {
 }
 
 size_t NTPUserDataLogger::GetPercentError(size_t errors, size_t events) const {
   return (100 * errors) / events;
 }