mac: Add metrics to record Bluetooth availability and capabilities.

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 eeaab506a61b8261dbfb6b575afd0e25d98a25c8..f5d2fd9e9a938d03a903ea2afdf68b482fd5463b 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -18923,6 +18923,13 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <summary>The number of clicks on the origin chip.</summary>
 </histogram>
 
+<histogram name="OSX.BluetoothAvailability" enum="BluetoothAvailability">
+  <owner>erikchen@chromium.org</owner>
+  <summary>
+    The availability and capabilities of the Bluetooth driver on OSX devices.

[Ilya Sherman, 2014/07/09 21:19:33]

Please document when this is logged, i.e. at startup.  Also, note that there is
some bias to logging a metric at startup: Users who relaunch Chrome more
frequently contribute more votes.  Is that an acceptable source of bias for this
metric?

[erikchen, 2014/07/11 17:25:44]

Adding documentation. As per offline discussion, this is an acceptable source of
bias.

+  </summary>
+</histogram>
+
 <histogram name="OSX.CatSixtyFour" enum="CatSixtyFour">
   <owner>mark@chromium.org</owner>
   <summary>The cat's flavor and how many bits there are in it.</summary>
@@ -35472,6 +35479,15 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   <int value="5" label="Blacklist disabled."/>
 </enum>
 
+<enum name="BluetoothAvailability" type="int">
+  <int value="0" label="Bluetooth not available."/>
+  <int value="1" label="Bluetooth available without LE."/>
+  <int value="2" label="Bluetooth available with LE."/>

[Ilya Sherman, 2014/07/09 21:19:33]

nit: Since the labels are displayed in the left column of a tabular layout on
the dashboard, shorter names are often easier to read.  Hence, I'd suggest
dropping the common "Bluetooth " prefix.

[erikchen, 2014/07/11 17:25:44]

Done.

+  <int value="3"
+      label="There was an unexpected error determining Bluetooth
+             availability."/>

[Ilya Sherman, 2014/07/09 21:19:33]

nit: I'd put this value first, so that it doesn't end up in the middle if you
ever decide to expand this enum.

[erikchen, 2014/07/11 17:25:44]

Done.

+</enum>
+
 <enum name="BluetoothPairingMethod" type="int">
   <int value="0" label="No user interaction required"/>
   <int value="1" label="PIN Code requested from user"/>