[GCM] Add port 443 fallback logic and histograms

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 4298a4f057290c8a42e4282423ef7d56270df0f3..ab23c41aa5abf50c86b6a7b87e1e3dca53884748 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -6561,11 +6561,24 @@ other types of suffix sets.
   <summary>Status code of the outcome of a GCM checkin request.</summary>
 </histogram>
 
+<histogram name="GCM.ConnectedViaProxy" enum="Boolean">
+  <owner>zea@chromium.org</owner>
+  <summary>Whether the GCM connection was made via a proxy or not.</summary>
+</histogram>
+
 <histogram name="GCM.ConnectionDisconnectErrorCode" enum="NetErrorCodes">
   <owner>zea@chromium.org</owner>
   <summary>Net error results from GCM disconnect events.</summary>
 </histogram>
 
+<histogram name="GCM.ConnectionEndpoint">
+  <owner>zea@chromium.org</owner>
+  <summary>
+    Index of the MCS endpoint to which a connection was made. See
+    gcm_client_impl.cc for endpoint definitions.

[Alexei Svitkine (slow), 2014/03/21 15:31:43]

Can they be enumerated with an enum entry in histograms.xml?

[Nicolas Zea, 2014/03/21 17:47:17]

Done.

+  </summary>
+</histogram>
+
 <histogram name="GCM.ConnectionFailureErrorCode" enum="NetErrorCodes">
   <owner>zea@chromium.org</owner>
   <summary>Net error results from GCM connection attempts.</summary>
@@ -6576,7 +6589,7 @@ other types of suffix sets.
   <summary>Reasons for GCM connection resets.</summary>
 </histogram>
 
-<histogram name="GCM.ConnectionSuccessRate">
+<histogram name="GCM.ConnectionSuccessRate" enum="BooleanSuccess">
   <owner>zea@chromium.org</owner>
   <summary>
     GCM connection success rate. Does not take into account login success. See