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 6741f7204ad614947874b51415bd06541fb06bc1..0490363b9a3841a1a790215f826b34b46cb256c8 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -1432,6 +1432,20 @@ other types of suffix sets.
   </summary>
 </histogram>
 
+<histogram name="Chrome.Android.Activity.CrashCounts" enum="AndroidActivityId">
+  <summary>
+    Indicates how many times each particular type of Activity was in the
+    foreground when a UMA session was terminated abnormally.

[Ilya Sherman, 2014/02/08 00:59:49]

What is an "UMA session"?  Do you mean an instance of Chrome for which UMA is
enabled?  A 5-minute window during which UMA stats are gathered?  Something
else?

[gone, 2014/02/08 01:16:32]

Goes with https://chrome-internal-review.googlesource.com/#/c/149216/

"Moves UmaSessionStats back to ChromeMobileApplication, redefining UMA sessions
to last as long as Chrome remains in the foreground."

Is there a more logical place to put the definition of a UMA session in Chromium
code, given that they're started and stopped from Clank code?

[Ilya Sherman, 2014/02/08 01:18:44]

I think it would be good to either document inline, or link to somewhere where
this is documented.  Stability stats are important, so it's important that the
documentation be especially clear and easy to understand for folks who might not
be very familiar with other UMA stats.

[Kibeom Kim (inactive), 2014/02/10 22:24:45]

Done.

+  </summary>
+</histogram>
+
+<histogram name="Chrome.Android.Activity.LaunchCounts" enum="AndroidActivityId">
+  <summary>
+    Indicates how many times each particular type of Activity was brought to the
+    foreground when a UMA session was active (i.e. launched at some point).
+  </summary>
+</histogram>
+
 <histogram name="Chrome.Browser.CrashedExecutionPhase" enum="ExecutionPhase">
   <summary>
     Indicates the execution phase the browser was in when the browser crashed.
@@ -21976,6 +21990,14 @@ other types of suffix sets.
   <int value="4" label="Snapped"/>
 </enum>
 
+<enum name="AndroidActivityId" type="int">
+  <int value="1" label="Unknown"/>

[Ilya Sherman, 2014/02/08 00:59:49]

Are you intentionally omitting bucket 0?  If so, why?

[gone, 2014/02/08 01:16:32]

Goes with the list at
https://codereview.chromium.org/137623002/diff/1040001/chrome/browser/android...

0 corresponds to a lack of Activity and is never expected to be sent back.  IIRC
we were asked to omit it.

[Ilya Sherman, 2014/02/08 01:18:44]

Makes sense.  Thanks :)

+  <int value="2" label="Main"/>
+  <int value="3" label="Preferences"/>
+  <int value="4" label="WebappActivity"/>
+  <int value="5" label="FullScreenActivity"/>
+</enum>
+
 <enum name="AndroidEvictionReason" type="int">
   <int value="0" label="TabUnusedTooLong"/>
   <int value="1" label="TabUnusedInSession"/>