Add metrics for search engine promo and search widget

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 9c8710c1e12704589b4ab52ca22379fdf2014244..96cfff6a0989157d3b37b6b6967266fd3c4c4c70 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -65549,6 +65549,45 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Search.SearchEngineListedInPromoDialog"
+    enum="OmniboxSearchEngineType">
+<!-- Name completed by histogram_suffixes name="SearchEnginePromoOrdering" and name="SearchEnginePromoDeviceType" -->
+  <owner>yusufo@chromium.org</owner>
+  <summary>
+    The search engines listed in the options for search engine promo. This
+    is an Android specific dialog prompting the user to pick a default search engine. The dialog
+    was shown on a device that had Chrome before it was first introduced.
+  </summary>
+</histogram>
+
+<histogram name="Search.SearchEngineSelectionInPromoDialog"
+    enum="OmniboxSearchEngineType">
+  <owner>yusufo@chromium.org</owner>
+  <summary>
+    The search engine selected by the user from the search engine promo. This is
+    an Android specific dialog prompting the user to pick a default search engine. The dialog was
+    shown on a device that had Chrome before it was first introduced.
+  </summary>
+</histogram>
+
+<histogram name="Search.PartnershipSearchPerformed"
+    enum="SearchEntryPoint">
+  <owner>yusufo@chromium.org</owner>
+  <summary>
+    The entry point used for all searches performed under partnership after the
+    Android search engine promo dialog was shown. This is a dialog prompting the user to
+    pick a default search engine. This metric is collected for every search query performed.
+  </summary>
+</histogram>
+
+<histogram name="Search.SearchWidgetUseAndDeviceInfo" enum="SearchWidgetUseInfo">
+  <owner>yusufo@chromium.org</owner>
+  <summary>
+    The current state for search widget use and whether the device is a
+    partnership device related with the Android Search Widget. Collected on every cold start.
+  </summary>
+</histogram>
+
 <histogram
     name="Security.HTTPBad.NavigationStartedAfterUserWarnedAboutSensitiveInput"
     units="ms">
@@ -92005,6 +92044,21 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <affected-histogram name="Event.Latency.ScrollUpdate.Wheel.TimeToHandled2"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="SearchEnginePromoDeviceType" separator=".">
+  <suffix name="ExistingDevice"/>
+  <suffix name="NewDevice"/>
+  <affected-histogram name="Search.SearchEngineListedInPromoDialog"/>
+  <affected-histogram name="Search.SearchEngineSelectionInPromoDialog"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="SearchEnginePromoOrdering" separator="."
+    ordering="prefix">
+  <suffix name="First"/>
+  <suffix name="Second"/>
+  <suffix name="Third"/>
+  <affected-histogram name="Search.SearchEngineListedInPromoDialog"/>

[Alexei Svitkine (slow), 2017/05/23 17:49:30]

If you want the two suffixes to be combined, you need one of them to list the
suffixed affected-histograms.

So if it's

Search.SearchEngineListedInPromoDialog.ExistingDevice.First

You want to have this entry list out
"Search.SearchEngineListedInPromoDialog.ExistingDevice" and
"Search.SearchEngineListedInPromoDialog.NewDevice" as affected histograms.

Although in this case you're using "prefix" ordering for this one which is
confusing - because I think that results in
"Search.First.SearchEngineListedInPromoDialog" which is probably not what you
want.

[Yusuf, 2017/05/23 18:10:31]

I actually do want "Search.First.SearchEngineListedInPromoDialog.ExistingDevice"
which I think reads better.

Listed the two suffixed names in the prefix definition.

[Alexei Svitkine (slow), 2017/05/23 20:03:10]

I find "Search.First" unintuitive - because reading that prefix doesn't tell you
what it's about. (I know you're trying to chain "First" with "SearchEngine" but
this is not what we do in terms of naming convention.)

How about Search.SearchEngineListedInPromoDialog.First.ExistingDevice? That can
be achieved by using the ordering="prefix,2" syntax.

[Yusuf, 2017/05/23 20:11:41]

Done.

+</histogram_suffixes>
+
 <histogram_suffixes name="SecurityInterstitialSBType" separator="."
     ordering="prefix">
   <suffix name="harmful"/>