Linux native notifications: Add server capabilities metrics

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 bfb4c9f8318b409301e8d416f3cbe24f677ed5d7..1af4fe0ec38df51a5f015b9d614e0108c693f33c 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -21230,6 +21230,18 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Freedesktop.Notifications.Capabilities"

[Mark P, 2017/05/03 19:20:40]

I think you're supposed to have base="true" here for histograms that have
suffixes.

[Tom (Use chromium acct), 2017/05/03 22:20:29]

Done.

+    enum="BooleanNotificationServerCapabilitySupported">

[Mark P, 2017/05/03 19:20:40]

nit: Don't bother adding a new enum.  Just use BooleanSupported.

(which by the way has 1==supported, which is what I think makes sense.  This is
the opposite of your enum.)

[Tom (Use chromium acct), 2017/05/03 22:20:29]

Done.

+<!-- Name completed by histogram_suffixes name="FreedesktopNotificationCapabilitiesId" -->
+
+  <owner>thomasanderson@chromium.org</owner>
+  <summary>
+    Whether the notification server supports the capability in question.  (Linux
+    only) Logged when the proxy to /org/Freedesktop/Notifications is set up
+    successfully.

[Mark P, 2017/05/03 19:20:40]

optional nit: ... which happens at most once on startup

[Tom (Use chromium acct), 2017/05/03 22:20:29]

Done.

+  </summary>
+</histogram>
+
 <histogram name="GCM.AndroidGcmReceiverError" enum="GcmReceiverStatus">
   <obsolete>
     Deprecated as of 01/2016. The error has been fixed by GCM. (crbug/580367)
@@ -25601,6 +25613,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Linux.NotificationPlatformBridge.InitializationStatus"
+    enum="LinuxNotificationBridgeStatusCode">
+  <owner>thomasanderson@chromium.org</owner>
+  <summary>
+    The status code for initializing NotificationPlatformBridgeLinux.  Logged on
+    each start up.
+  </summary>
+</histogram>
+
 <histogram name="Linux.SandboxStatus" enum="LinuxSandboxStatus">
   <owner>rickyz@chromium.org</owner>
   <summary>
@@ -43833,6 +43854,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Notifications.UsingNativeNotificationCenter"
+    enum="BooleanNativeNotifications">
+  <owner>thomasanderson@chromium.org</owner>
+  <summary>
+    Indicates if Chrome is using system notifications or the Chrome notification
+    center.  Logged on each start up.

[Mark P, 2017/05/03 19:20:40]

Linux only?

[Tom (Use chromium acct), 2017/05/03 22:20:29]

Nope, all platforms now.  This was changed from the first patch set.

+  </summary>
+</histogram>
+
 <histogram name="Notifications.XPCConnectionEvent" enum="XPCConnectionEvent">
   <owner>miguelg@chromium.org</owner>
   <owner>rsesek@chromium.org</owner>
@@ -85556,6 +85586,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Missing data in disk cache"/>
 </enum>
 
+<enum name="BooleanNativeNotifications" type="int">
+  <int value="0" label="Using Chrome notifications"/>
+  <int value="1" label="Using native notifications"/>
+</enum>
+
 <enum name="BooleanNavPreloadFinishedFirst" type="int">
   <int value="0" label="Worker preparation finished first"/>
   <int value="1" label="Navigation preload response arrived first"/>
@@ -85566,6 +85601,11 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="1" label="Needs to be clearred"/>
 </enum>
 
+<enum name="BooleanNotificationServerCapabilitySupported" type="int">
+  <int value="0" label="Server supports capability"/>
+  <int value="1" label="Server does not support capability"/>
+</enum>
+
 <enum name="BooleanNullStream" type="int">
   <int value="0" label="Stream is not a nullptr"/>
   <int value="1" label="Stream is a nullptr"/>
@@ -102967,6 +103007,13 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="20" label="2.29"/>
 </enum>
 
+<enum name="LinuxNotificationBridgeStatusCode" type="int">
+  <int value="0" label="success"/>
+  <int value="1" label="native notifications not supported"/>
+  <int value="2" label="missing required capabilities"/>
+  <int value="3" label="could not connect to signals"/>
+</enum>
+
 <enum name="LinuxSandboxStatus" type="int">
   <int value="0" label="none"/>
   <int value="1" label="suid"/>
@@ -121449,6 +121496,20 @@ from previous Chrome versions.
   <affected-histogram name="FirstUserAction.BackgroundTime.MainIntent"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="FreedesktopNotificationCapabilitiesId" separator=".">
+  <suffix name="ActionIcons" label="action-icons capability"/>
+  <suffix name="Actions" label="actions capability"/>
+  <suffix name="Body" label="body capability"/>
+  <suffix name="BodyHyperlinks" label="body-hyperlinks capability"/>
+  <suffix name="BodyImages" label="body-images capability"/>
+  <suffix name="BodyMarkup" label="body-markup capability"/>
+  <suffix name="IconMulti" label="icon-multi capability"/>
+  <suffix name="IconStatic" label="icon-static capability"/>
+  <suffix name="Persistence" label="persistence capability"/>
+  <suffix name="Sound" label="sound capability"/>
+  <affected-histogram name="Freedesktop.Notifications.Capabilities"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="FromGWS">
   <suffix name="FromGWS"
       label="Only page loads that are a result of a navigation from a web