[GCM] Track connection failures properly

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 2554201fa7227597ea70145b4d0ed5e6c7f89ed8..d224255fc92c0a1bae8f6f1daa1880def4866aba 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -5485,6 +5485,24 @@ other types of suffix sets.
   <summary>Net error results from GCM connection attempts.</summary>
 </histogram>
 
+<histogram name="GCM.ConnectionResetReason" enum="GCMConnectionResetReason">
+  <summary>Reasons for GCM connection resets.</summary>
+</histogram>
+
+<histogram name="GCM.ConnectionSuccessRate">
+  <summary>
+    GCM connection success rate. Does not take into account login success. See
+    GCM.ConnectionFailureErrorCode for a breakdown of connection failure
+    reasons.
+  </summary>
+</histogram>
+
+<histogram name="GCM.ConnectionUpTime" units="milliseconds">
+  <summary>
+    Time (from login until reset) that a GCM connection was active

[Alexei Svitkine (slow), 2014/02/12 22:15:37]

Nit: add a .

[Nicolas Zea, 2014/02/12 22:27:35]

Done.

+  </summary>
+</histogram>
+
 <histogram name="GCM.NumThrottledApps">
   <summary>
     Number of applications hitting GCM per-app outstanding message limits at
@@ -26380,6 +26398,13 @@ other types of suffix sets.
   <int value="8" label="Overflow"/>
 </enum>
 
+<enum name="GCMConnectionResetReason" type="int">
+  <int value="0" label="Login failure"/>
+  <int value="1" label="Close command"/>
+  <int value="2" label="Heartbeat failure"/>
+  <int value="3" label="Socket failure"/>
+</enum>
+
 <enum name="GCMRegistrationRequestStatus" type="int">
   <int value="0" label="Success (this is not logged currently)"/>
   <int value="1" label="Invalid parameters"/>