Let MetricsService know about some Android Activities

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 9497be61e3743932e72ba203ee646555f0e155d8..0cfc839152911d97d552fa46cc459a6831fe5d7a 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -1416,6 +1416,20 @@ 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.
+  </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.
@@ -21570,6 +21584,14 @@ other types of suffix sets.
   <int value="4" label="Snapped"/>
 </enum>
 
+<enum name="AndroidActivityId" type="int">
+  <int value="1" label="Unknown"/>
+  <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"/>