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 ff32bcbb4dcbdd10ac38dfa5a80fd58f1e07bb7e..0c46b477edee317aae3835cc6a9db38f4be4366d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2712,24 +2712,71 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
-<histogram name="Bluetooth.RequestDevice.Outcome"
-    enum="BluetoothRequestDeviceOutcome">
+<histogram name="Bluetooth.Web.FunctionCall.Count" enum="WebBluetoothFunction">
   <owner>jyasskin@chromium.org</owner>
   <owner>ortuno@chromium.org</owner>
   <owner>scheib@chromium.org</owner>
   <summary>
-    Records the result of a navigator.bluetooth.requestDevice() call. Used to
-    understand what errors developers are getting so we can target efforts
-    toward the most common ones.
+    Counts the number of times each call to a WebBluetooth function is done.
   </summary>
 </histogram>
 
-<histogram name="Bluetooth.Web.FunctionCall.Count" enum="WebBluetoothFunction">
+<histogram name="Bluetooth.Web.RequestDevice.Filters.Count" units="filters">

[Jeffrey Yasskin, 2015/08/05 19:03:49]

I'm not sure we should include this. It's only 1 dimension of the filters
argument, and I don't have any picture of how we'd improve the API or
implementation just knowing how many or'ed alternatives people are passing in.

[ortuno, 2015/08/05 22:05:12]

If we plan on informing the users the services that a website is trying to
access then this data could help with the UI decisions: Knowing how many filters
are normally used, how many services are normally used when scanning, etc. could
be used the same way the number of devices was used to decide how big the BT
device chooser is on ChromeOS.

[Jeffrey Yasskin, 2015/08/05 22:55:41]

For that, we need the total number of services, including both filters and
optional services. We don't yet compute that, but we'll need to in order to
store the allowed services set. Let's do that. There's a start in
ComputeScanFilter(). This would be named something like
"Bluetooth.Web.RequestDevice.AllowedServices.Count", right?

[ortuno, 2015/08/10 20:05:50]

I don't see the harm in having a breakdown of the allowed services and the
number of filters. I can imagine a general purpose ble website scanning for each
service in a different filter. We surely want to express that differently than
all services in a single filter.

   <owner>jyasskin@chromium.org</owner>
   <owner>ortuno@chromium.org</owner>
   <owner>scheib@chromium.org</owner>
   <summary>
-    Counts the number of times each call to a WebBluetooth function is done.
+    Records how many filters are used when scanning. This results will help us
+    better understand the uses of the API and make changes according to
+    developers' behavior.
+  </summary>
+</histogram>
+
+<histogram name="Bluetooth.Web.RequestDevice.Filters.Services"

[Jeffrey Yasskin, 2015/08/05 19:03:49]

This might be helpful in future API development, but I don't think it'll help
the Web Bluetooth API. Even to help with future development, I think we're going
to want to watch more than the standardized services, and histograms aren't
really a good tool for a 128-bit space.

If we do use this, all standardized services so far have UUIDs of the form
000018xy-0000-1000-8000-00805f9b34fb. Let's just pass the xy to the enumeration?
Maybe use 0xFF for the "unknown" value. We'll need to re-do it when they
allocate more than 255 services, but that'll take a while.

[ortuno, 2015/08/05 22:05:12]

OK. So instead of having the enums we would just have a count histogram?

[Jeffrey Yasskin, 2015/08/05 22:55:41]

I'd prefer to just have the AllowedServices.Count histogram until we have a
specific use in mind for recording standardized services.

One specific use might be in checking whether people use a lot of non-standard
services. I believe they'll use more non-standard than standard ones, but I
could be wrong. For that, we need a 2-bit bitset: has-standard-services (defined
as having 16-bit UUIDs?) and has-non-standard-services. I could see recording
this for both the filters and the optional_services.

When looking at higher-level APIs to standardize, I think we'll be better off
looking at npm and bower for popular libraries, than just looking at which
standardized services are used. Once we have some candidates, we could add a
more targeted histogram to decide between them, but I don't think we should just
record everything up front.

+    enum="GATTServices">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Records what GATT Services are used when scanning. This will help us know if
+    we should build an API for specific services rather than a general Bluetooth
+    API.
+  </summary>
+</histogram>
+
+<histogram name="Bluetooth.Web.RequestDevice.OptionalServices.Count"

[Jeffrey Yasskin, 2015/08/05 19:03:49]

Again, what do we learn from the count of optional services? At least this is
the whole length of the argument, but I'm having trouble thinking of what we'll
use it for.

[ortuno, 2015/08/05 22:05:12]

I think this would give us a pretty good idea of what's the
Advertised/Non-advertised service ratio. Similarly knowing which services are
used here would tell us which services are advertised and which aren't.

[Jeffrey Yasskin, 2015/08/05 22:55:41]

If we want to know what fraction of services devices tend to advertise, we
should collect that in the discovery code, not from requestDevice() calls.

+    units="filters">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Records how many optional services are used when scanning. This results will
+    help us better understand the uses of the API and make changes according to
+    developers' behavior.
+  </summary>
+</histogram>
+
+<histogram name="Bluetooth.Web.RequestDevice.OptionalServices.Services"
+    units="GATTServices">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Records how many optional services are used when scanning. This results will
+    help us better understand the uses of the API and make changes according to
+    developers' behavior.
+  </summary>
+</histogram>
+
+<histogram name="Bluetooth.Web.RequestDevice.Outcome"
+    enum="WebBluetoothRequestDeviceOutcome">
+  <owner>jyasskin@chromium.org</owner>
+  <owner>ortuno@chromium.org</owner>
+  <owner>scheib@chromium.org</owner>
+  <summary>
+    Records the result of a navigator.bluetooth.requestDevice() call. Used to
+    understand what errors developers are getting so we can target efforts
+    toward the most common ones.
   </summary>
 </histogram>
 
@@ -51613,17 +51660,6 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="8" label="Unknown or unhandler error"/>
 </enum>
 
-<enum name="BluetoothRequestDeviceOutcome" type="int">
-  <int value="0" label="Success"/>
-  <int value="1" label="No Bluetooth adapter"/>
-  <int value="2" label="No RenderFrameHost for message source"/>
-  <int value="3" label="Discovery start failed"/>
-  <int value="4" label="Discovery stop failed"/>
-  <int value="5" label="No matching devices found"/>
-  <int value="6" label="Bluetooth Adapter not present"/>
-  <int value="7" label="Bluetooth Adapter was off"/>
-</enum>
-
 <enum name="BookmarksExperimentState" type="int">
   <int value="0" label="No experiment"/>
   <int value="1" label="Experiment enabled (sync)"/>
@@ -58805,6 +58841,42 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   <int value="8" label="Overflow"/>
 </enum>
 
+<enum name="GATTServices" type="int">
+  <int value="0" label="unknown"/>
+  <int value="1" label="alert_notification"/>
+  <int value="2" label="automation_io"/>
+  <int value="3" label="battery_service"/>
+  <int value="4" label="blood_pressure"/>
+  <int value="5" label="body_composition"/>
+  <int value="6" label="bond_management"/>
+  <int value="7" label="continuous_glucose_monitoring"/>
+  <int value="8" label="current_time"/>
+  <int value="9" label="cycling_power"/>
+  <int value="10" label="cycling_speed_and_cadence"/>
+  <int value="11" label="device_information"/>
+  <int value="12" label="environmental_sensing"/>
+  <int value="13" label="generic_access"/>
+  <int value="14" label="generic_attribute"/>
+  <int value="15" label="glucose"/>
+  <int value="16" label="health_thermometer"/>
+  <int value="17" label="heart_rate"/>
+  <int value="18" label="human_interface_device"/>
+  <int value="19" label="immediate_alert"/>
+  <int value="20" label="indoor_positioning"/>
+  <int value="21" label="internet_protocol_support"/>
+  <int value="22" label="link_loss"/>
+  <int value="23" label="location_and_navigation"/>
+  <int value="24" label="next_dst_change"/>
+  <int value="25" label="phone_alert_status"/>
+  <int value="26" label="pulse_oximeter"/>
+  <int value="27" label="reference_time_update"/>
+  <int value="28" label="running_speed_and_cadence"/>
+  <int value="29" label="scan_parameters"/>
+  <int value="30" label="tx_power"/>
+  <int value="31" label="user_data"/>
+  <int value="32" label="weight_scale"/>
+</enum>
+
 <enum name="GCMCheckinRequestStatus" type="int">
   <int value="0" label="Success"/>
   <int value="1" label="URL fetching failed"/>
@@ -71038,6 +71110,17 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="5" label="Characteristic.writeValue()"/>
 </enum>
 
+<enum name="WebBluetoothRequestDeviceOutcome" type="int">
+  <int value="0" label="Success"/>
+  <int value="1" label="No Bluetooth adapter"/>
+  <int value="2" label="No RenderFrameHost for message source"/>
+  <int value="3" label="Discovery start failed"/>
+  <int value="4" label="Discovery stop failed"/>
+  <int value="5" label="No matching devices found"/>
+  <int value="6" label="Bluetooth Adapter not present"/>
+  <int value="7" label="Bluetooth Adapter was off"/>
+</enum>
+
 <enum name="WebFontCacheHit" type="int">
   <int value="0" label="Miss"/>
   <int value="1" label="Hit"/>