Log an action at the same time as the NewTabPage.MostVisited histogram.

The NewTabPage.MostVisited histogram is used as part of a high level guiding metric. We're trying to consolidate these metrics as user actions to improve query speeds and enable new analysis.

BUG=b/161525144

Change-Id: I25a0f4f90a8f11c14ae5dab22ad199917440d719
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2508133Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Commit-Queue: Jesse Doherty <jwd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822840}

components/ntp_tiles/metrics.cc

@@ -8,6 +8,7 @@
 
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/metrics/user_metrics.h"
 #include "base/notreached.h"
 #include "base/strings/stringprintf.h"
 #include "components/ntp_tiles/constants.h"
@@ -151,6 +152,7 @@ void RecordTileImpression(const NTPTileImpression& impression) {
 void RecordTileClick(const NTPTileImpression& impression) {
   UMA_HISTOGRAM_ENUMERATION("NewTabPage.MostVisited", impression.index,
                             kMaxNumTiles);
+  base::RecordAction(base::UserMetricsAction("NewTabPage.MostVisited.Clicked"));
 
   std::string source_name = GetSourceHistogramName(impression.source);
   base::UmaHistogramExactLinear(

tools/metrics/actions/actions.xml

@@ -16091,6 +16091,22 @@ should be able to be added at any place in this file.
   </description>
 </action>
 
+<action name="NewTabPage.MostVisited.Clicked">
+  <owner>justincohen@chromium.org</owner>
+  <owner>mastiz@chromium.org</owner>
+  <owner>tiborg@chromium.org</owner>
+  <owner>yyushkina@chromium.org</owner>
+  <owner>chrome-analysis-team@google.com</owner>
+  <owner>chrome-desktop-ntp@google.com</owner>
+  <description>
+    The user clicked on a most visited tile. This action is logged every time
+    the NewTabPage.MostVisited histogram is logged.
+
+    This action is of special interest to the chrome-analysis-team@. Do not
+    change its semantics or retire it without talking to them first.
+  </description>
+</action>
+
 <action name="NewTabPage.Promo.EnhancedProtectionPromo.Accepted">
   <owner>bdea@chromium.org</owner>
   <owner>chrome-safebrowsing-alerts@google.com</owner>

tools/metrics/histograms/histograms_xml/new_tab_page/histograms.xml

@@ -843,6 +843,9 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
     Histogram for user clicks of the most visited tile. The value is equal to
     the index of the tile.
 
+    The user action NewTabPage.MostVisited.Clicked is also logged at the same
+    time as this histogram.
+
     This histogram is of special interest to the chrome-analysis-team@. Do not
     change its semantics or retire it without talking to them first.
   </summary>