Settings reset prompt: add UMA metrics reporting.

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 da1f11b7838f7d0f76258be3bb670165f79d7615..29285147314c397ee060b1b2d6bb379b417ebb01 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -64126,6 +64126,83 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="SettingsResetPrompt.DefaultSearchResetState"
+    enum="SettingsResetPromptResetState">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    Indicates whether the settings reset prompt is enabled for the user's
+    default search setting, or the reason for it being disabled.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.DelayBeforePromptParam" units="seconds">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    The feature parameter determining the amount of time to wait after startup
+    before attempting to show the settings reset prompt.

[jwd, 2017/03/07 18:08:38]

This is just coming from the variations config, yeah? Why transmit this back?
(I'm not saying you shouldn't but it's not clear you need it)

[alito, 2017/03/07 20:42:05]

This is in case we decide to experiment with the delay to see if it makes a
difference in the number of users who accept the prompt. We could then easily
separate users based on the value of this histogram. Let me know if there is a
better way of supporting this use case.

[jwd, 2017/03/07 20:53:00]

I would support this use case using experiments and variations. As long as you
create a new experiment/group for each param value, you would be able to
separate the clients. It would also work with our dashboards. Separating based
on this histogram will require custom analysis.

If you end up keeping this histogram, can you add to the summary a description
of when it's logged. E.g. once on startup, once a session, every record,
whenever the dialog is shown.

[alito, 2017/03/07 21:04:01]

Lets keep this for now. I've added description of when this is logged.

[alito, 2017/03/07 21:04:01]

Done.

+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.DialogState"
+    enum="SettingsResetPromptDialogState">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    Indicates whether the settings reset prompt dialog was shown to the user and
+    how the user interacted with it.

[jwd, 2017/03/07 18:08:38]

This is fine, but many of our tools assume that enum histograms sum to a
meaningful value, which is used to compute bucket proportions. Is there a reason
you want the shown count, and results grouped into one histogram. I'm fine with
you keeping it as is, mostly an FYI.

+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.HomepageResetState"
+    enum="SettingsResetPromptResetState">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    Indicates whether the settings reset prompt is enabled for the user's
+    homepage setting, or the reason for it being disabled.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.NumberOfExtensionsToDisable"
+    units="extensions">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    The number of extensions that will be disabled if the user accepts the
+    settings reset prompt.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.PromptWanted" enum="Boolean">

[jwd, 2017/03/07 18:08:38]

I'm not sure Wanted is the right word here, it implies user preference to me.

[jwd, 2017/03/07 18:08:38]

Can you create a more specific enum for this, maybe something like
BooleanWanted, with meaningfully labeled enum values.

[alito, 2017/03/07 20:42:05]

Done.

[alito, 2017/03/07 20:42:05]

Changed to PromptRequired.

+  <owner>alito@chromium.org</owner>
+  <summary>
+    Indicates whether the settings reset prompt should be shown to the user
+    based on the state of the user's settings.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.StartupUrlsResetState"

[jwd, 2017/03/07 18:08:38]

I'd change the *ResetState histograms to be reformulated using suffixes. There
are instructions at the top of the file, basically you'd add a histogram
SettingsResetPrompt.ResetState, with a description that applies to all the
cases. Then you'd add suffixes to it (StartupUrls, Homepage), with specific
added description.

[alito, 2017/03/07 20:42:05]

Done.

+    enum="SettingsResetPromptResetState">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    Indicates whether the settings reset prompt is enabled for the user's
+    startup pages setting, or the reason for it being disabled.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.TimeUntilAccepted" units="ms">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    The time between the settings reset prompt dialog being shown and the user
+    accepting the prompt.
+  </summary>
+</histogram>
+
+<histogram name="SettingsResetPrompt.TimeUntilDeclined" units="ms">
+  <owner>alito@chromium.org</owner>
+  <summary>
+    The time between the settings reset prompt dialog being shown and the user
+    declining the prompt.
+  </summary>
+</histogram>
+
 <histogram name="Setup.Install.ApplyArchivePatchTime" units="ms">
   <owner>grt@chromium.org</owner>
   <summary>
@@ -108521,6 +108598,22 @@ from previous Chrome versions.
   <int value="9" label="Bad time_between_prompts_seconds param"/>
 </enum>
 
+<enum name="SettingsResetPromptDialogState" type="int">
+  <int value="1" label="Shown"/>
+  <int value="2" label="Accepted"/>
+  <int value="3" label="Declined"/>
+</enum>
+
+<enum name="SettingsResetPromptResetState" type="int">
+  <int value="1" label="Reset required"/>
+  <int value="2" label="No reset required due to domain not matched"/>
+  <int value="3" label="No reset required due to already prompted for setting"/>
+  <int value="4" label="No reset required due to recently prompted"/>

[jwd, 2017/03/07 18:08:38]

I'd recommend slightly shorter labels. Our tools prefer shorter, longer does
work though. You can also add a longer description in the body of the <int> tag.
I'd suggest changing the labels to "Recently prompted, no reset required"
maybe?, so that the more relevant info is first.

[alito, 2017/03/07 20:42:05]

Done.

+  <int value="5"
+      label="No reset required due to other setting requiring reset"/>
+  <int value="6" label="No reset required due to policy"/>
+</enum>
+
 <enum name="SettingsSections" type="int">
   <summary>
     A collection of sections from chrome://settings. Used for metrics about