Field trial removing tiles from NTP if URL is already open - for 1993 clients

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index d9e7c5c7caa1650249199d4a499bac975c484c5e..281d8ee69249c58a0fe0e0c13040aed38333acb5 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -7178,6 +7178,13 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="NewTabPage.MostVisitedTilePlacementExperiment"
+    enum="NtpTileExperimentActions">
+  <summary>
+    Histogram of actions carried out by Most Visited Tile Placement experiment.

[beaudoin, 2013/06/20 21:55:44]

This could be a bit more detailed. As such, it's unclear what this is for.
Explain that we want to identify the cases where the experiment could not
operate as expected and the reason for it.

[annark1, 2013/07/04 18:29:15]

Done.

+  </summary>
+</histogram>
+
 <histogram name="NewTabPage.NonVisibleScreenshots">
   <summary>
     The number of screenshots that were cached for the non-visible but ranked
@@ -15877,6 +15884,17 @@ other types of suffix sets.
   <int value="2" label="NTP Promo link clicked"/>
 </enum>
 
+<enum name="NtpTileExperimentActions" type="int">
+  <summary>
+    The types of actions performed by the Most Visited Tile Placement experiment

[beaudoin, 2013/06/20 21:55:44]

Same here, a bit more details.

[annark1, 2013/07/04 18:29:15]

Done.

+  </summary>
+  <int value="0" label="Removed URL that was already open in browser"/>
+  <int value="1" label="Didn't remove URL, too few suggestions in MV"/>
+  <int value="2" label="Too few URLs, didn't flip tiles 1 and 8"/>
+  <int value="3" label="Too few URLs, didn't flip tiles 1 and 4"/>
+  <int value="4" label="No URL, couldn't flip any tiles"/>
+</enum>
+
 <enum name="OfflineStatus" type="int">
   <int value="0" label="Fresh data load from Cache"/>
   <int value="1" label="Successful network request (validation or fetch)."/>