Add metric to record users opening a new NTP.

tools/metrics/actions/actions.xml

Index: tools/metrics/actions/actions.xml
diff --git a/tools/metrics/actions/actions.xml b/tools/metrics/actions/actions.xml
index 0ed10fe9f5c36a6ef0c4853eb907cb6ed445222d..6a6472d5d3cad2c204ef135e3222a9a39eab5f02 100644
--- a/tools/metrics/actions/actions.xml
+++ b/tools/metrics/actions/actions.xml
@@ -9961,6 +9961,14 @@ should be able to be added at any place in this file.
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="MobileNTPOpenedInNewTab">
+  <owner>fhorschig@chromium.org</owner>
+  <description>
+    The user manually created a New Tab Page (NTP) in a new tab that has not

[Michael van Ouwerkerk, 2017/03/14 16:07:36]

Have you confirmed that this indeed is not logged at startup when an NTP is
created? Because in that case the user did not exactly manually create one.

[fhorschig, 2017/03/14 17:30:45]

Adjusted description to match my intention.
If you like, I can exclude the "manually", too but by opening chrome,
the user triggers that NTP. I know, the line is blurry here but I want it 
to be logged (and confirmed that), because that instantiation is never 
happening due to a navigation which is what I really want to figure out
by measuring this.
If it (surprisingly) turns out to be unwanted, we can use the LoadType 
metric to correct for cold starts. For warm starts, the navigation rules
should apply as usual.

+    been shown before.
+  </description>
+</action>
+
 <action name="MobileNTPRecentlyClosed">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>