Obsolete old Google Now launcher user actions.

Change-Id: Ifdf8969673ad991b8235945c12d7f10a31be31bd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2320137
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Reviewed-by: Travis Skare <skare@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792260}

tools/metrics/actions/actions.xml

@@ -7027,6 +7027,7 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.ButtonClicked0">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>
@@ -7035,6 +7036,7 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.ButtonClicked1">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>
@@ -7043,12 +7045,14 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.Dismissed">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>User dismissed a Now Notification.</description>
 </action>
 
 <action name="GoogleNow.MessageCenter.NotificationPoppedUp">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>
@@ -7057,6 +7061,7 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.MessageClicked">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>
@@ -7065,6 +7070,7 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.WelcomeToastClickedNo">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>
@@ -7074,6 +7080,7 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.WelcomeToastClickedYes">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>
@@ -7082,6 +7089,7 @@ should be able to be added at any place in this file.
 </action>
 
 <action name="GoogleNow.WelcomeToastDismissed">
+  <obsolete>Feature removed March 2017.</obsolete>
   <owner>robliao@chromium.org</owner>
   <owner>skare@chromium.org</owner>
   <description>