Create mappings for unmapped GCM-related 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 db79a3ce5c1c80b78b99517e17a4c6ee11bfab69..474b198bbf9794f3521998612dba9beda0baa975 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -17675,6 +17675,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GCM.DataMessageReceived" units="messages">
+  <owner>peter@chromium.org</owner>
+  <summary>
+    Number of DATA_MESSAGE messages for registered application IDs and
+    DELETED_MESSAGES messages for any registration ID received from Google Cloud
+    Messaging. Recorded when processing the received message.
+  </summary>
+</histogram>
+
 <histogram name="GCM.FirstReceivedDataMessageLatencyAfterConnection" units="ms">
   <owner>juyik@chromium.org</owner>
   <summary>
@@ -17691,6 +17700,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GCM.IncomingSendErrors" units="messages">
+  <owner>peter@chromium.org</owner>
+  <summary>
+    Number of SEND_ERROR messages received from Google Cloud Messaging. Recorded
+    when processing the received message.
+  </summary>
+</histogram>
+
 <histogram name="GCM.LoadStatus" enum="GCMLoadStatus">
   <owner>jianli@chromium.org</owner>
   <summary>Status code of loading from the persistent GCM store.</summary>
@@ -17754,6 +17771,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GCM.RegistrationRequest" units="requests">
+  <owner>peter@chromium.org</owner>
+  <summary>
+    Number of registration requests sent to Google Cloud Messaging. Recorded
+    immediately after the request has started.
+  </summary>
+</histogram>
+
 <histogram name="GCM.RegistrationRequestStatus"
     enum="GCMRegistrationRequestStatus">
   <owner>juyik@chromium.org</owner>
@@ -17800,6 +17825,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GCM.SendMessageStatus" enum="GCMSendMessageStatus">
+  <owner>peter@chromium.org</owner>
+  <summary>
+    Result of sending an upstream message through Google Cloud Messaging.
+    Recorded when the message has either been queued, sent, or has been dropped
+    because it expired or an error happened.
+  </summary>
+</histogram>
+
 <histogram name="GCM.StoreDestroySucceeded" enum="BooleanSuccess">
   <owner>zea@chromium.org</owner>
   <summary>
@@ -17836,6 +17870,14 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="GCM.UnregistrationRequest" units="requests">
+  <owner>peter@chromium.org</owner>
+  <summary>
+    Number of unregistration requests sent to Google Cloud Messaging. Recorded
+    immediately after the request has started.
+  </summary>
+</histogram>
+
 <histogram name="GCM.UnregistrationRequestStatus"
     enum="GCMUnregistrationRequestStatus">
   <owner>juyik@chromium.org</owner>
@@ -83671,6 +83713,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Infinite store reset"/>
 </enum>
 
+<enum name="GCMSendMessageStatus" type="int">
+  <int value="0" label="Message queued"/>
+  <int value="1" label="Message sent to the server, ACK received"/>
+  <int value="2" label="Message not saved, exceeded app queue size"/>
+  <int value="3" label="Message not saved, exceeded total queue size"/>
+  <int value="4" label="Message too large to send"/>
+  <int value="5" label="Message has zero TTL and no open connection"/>
+  <int value="6" label="Message TTL exceeded"/>
+</enum>
+
 <enum name="GCMUnregistrationRequestStatus" type="int">
   <int value="0" label="Success"/>
   <int value="1" label="URL fetching failed"/>