Add histograms for location timings for Android omnibox queries.

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 168e7f1d8d98a2386989a883126132cb98306c9a..8cfaf9a39f6e76ef9ca4fe9ee9389611164f875f 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -19356,6 +19356,15 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Geolocation.Header.LocationAge" units="ms">

[Ilya Sherman, 2016/12/15 23:06:19]

nit: Please add the base="true" attribute, which just means that there's no
histogram named "Geolocation.Header.LocationAge" -- it's just a shared prefix. 
(And, if you take my advice about histogram_suffixes below, please do the same
for the intermediary suffixes.  I forget where exactly the base attribute goes
for those, but there should be some examples in this file.)

[pdyson, 2016/12/16 05:03:31]

Done.

See below for issue with base="true" in histogram_suffixes.

+  <owner>kcarattini@chromium.org</owner>
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    For Geolocation requests from the omnibox on Android, the time since the
+    location was most recently acquired.

[Ilya Sherman, 2016/12/15 23:06:19]

What's recorded here if no location has been acquired?  Is it the same as for
Geolocation.Header.TimeListening?

[pdyson, 2016/12/16 05:03:31]

Done.

+  </summary>
+</histogram>
+
 <histogram name="Geolocation.Header.PermissionState"
     enum="GeolocationHeaderPermissionState">
   <owner>kcarattini@chromium.org</owner>
@@ -19367,6 +19376,16 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="Geolocation.Header.TimeListening" units="ms">
+  <owner>kcarattini@chromium.org</owner>
+  <owner>dominickn@chromium.org</owner>
+  <summary>
+    For Geolocation requests from the omnibox on Android, the time since the
+    location was first acquired. If no location has been aquired, the maximum

[Ilya Sherman, 2016/12/15 23:06:19]

nit: s/aquired/acquired

[pdyson, 2016/12/16 05:03:31]

Done.

+    bucket is incremented.
+  </summary>
+</histogram>
+
 <histogram name="Geolocation.InfoBarDelegate.Event"
     enum="GeolocationInfoBarDelegateEvent">
   <obsolete>
@@ -110428,6 +110447,40 @@ value.
   <affected-histogram name="LocalStorage.RendererTimeToPrimeLocalStorage"/>
 </histogram_suffixes>
 
+<histogram_suffixes name="LocationMode">

[Ilya Sherman, 2016/12/15 23:06:19]

nit: I think you need to specify separator=".", as the default IIRC is an
underscore.

[pdyson, 2016/12/16 05:03:31]

Done.

+  <suffix name="BatterySaving"
+      label="This histogram is for location mode Battery Saving."/>
+  <suffix name="GpsOnly" label="This histogram is for location mode GPS Only."/>
+  <suffix name="HighAccuracy"
+      label="This histogram is for location mode High Accuracy."/>
+  <affected-histogram name="Geolocation.Header.LocationAge"/>
+</histogram_suffixes>
+
+<histogram_suffixes name="LocationModeAttachedStatus">
+  <suffix name="BatterySavingLocationAttached"
+      label="This histogram is for location mode Battery Saving when the
+             location was successfully attached to the request."/>
+  <suffix name="GpsOnlyLocationAttached"
+      label="This histogram is for location mode GPS Only when the location
+             was successfully attached to the request."/>
+  <suffix name="HighAccuracyLocationAttached"
+      label="This histogram is for location mode High Accuracy when the
+             location was successfully attached to the request."/>
+  <suffix name="BatterySavingLocationNotAttached"
+      label="This histogram is for location mode Battery Saving when the
+             location was not attached to the request. A location may not be
+             attached if it is too old or if the permissions do not allow it."/>
+  <suffix name="GpsOnlyLocationNotAttached"
+      label="This histogram is for location mode GPS Only when the location
+             was not attached to the request. A location may not be attached
+             if it is too old or if the permissions do not allow it."/>
+  <suffix name="HighAccuracyLocationNotAttached"
+      label="This histogram is for location mode High Accuracy when the
+             location was not attached to the request. A location may not be
+             attached if it is too old or if the permissions do not allow it."/>

[Ilya Sherman, 2016/12/15 23:06:19]

You can use two levels of histogram_suffixes for the Attached/NotAttached
variants, i.e.

<histogram_suffixes ...>
  <suffix name="Attached" ...>
  <suffix name="NotAttached" ...>
  <affected-histogram name="Geolocation.Header.TimeListening.BatterySaving"/>
  <affected-histogram name="Geolocation.Header.TimeListening.GpsOnly"/>
  <affected-histogram name="Geolocation.Header.TimeListening.HighAccuracy"/>
</histogram_suffixes>

[pdyson, 2016/12/16 05:03:31]

Done.

In histogram_suffixes the base="true" attribute goes on the <suffix>. However,
for LocationMode those suffixes should be base="true" for one affected-histogram
but not for the other, so I have left it out.

[Ilya Sherman, 2016/12/16 08:57:30]

Yep, that's fine -- the base="true" attribute just keeps the histograms from
popping up in the list of histograms on the dashboard, so it's not a big deal if
it's omitted in some cases.

+  <affected-histogram name="Geolocation.Header.TimeListening"/>
+</histogram_suffixes>
+
 <histogram_suffixes name="LockExistingCachedImage" separator=".">
   <suffix name="Software.EVENTUALLY" label="Eventually bin for software"/>
   <suffix name="Software.NOW" label="Now bin for software"/>