Add instrumentation for password autofill and Credential Manager API user flows.

tools/metrics/actions/actions.xml

 <!--
 Copyright 2014 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file.
 -->
 
 <!--
 This file is a comprehensive list of Chrome user actions along with the owner
 and description for each user action. A user action should be tied to an actual
 action taken by a user. It should be logged immediately after a user takes the
@@ skipping 2244 matching lines @@
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="BrowserPlugin.PermissionDeny.PointerLock">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
   <obsolete>This permission has been moved to the chrome layer.</obsolete>
 </action>
 
+<action name="CMAPI_AccountChooser_Click">

[Ilya Sherman, 2016/06/30 21:11:35]

nit: Please spell out "Credential Manager" -- "CMAPI" is a bit hard to decode
otherwise.

[vasilii, 2016/07/01 12:58:59]

Done.

+  <owner>vasilii@chromium.org</owner>
+  <description>User chose a credential via the account chooser</description>
+</action>
+
+<action name="CMAPI_AccountChooser_Dismiss">
+  <owner>vasilii@chromium.org</owner>
+  <description>User dismissed the account chooser</description>
+</action>
+
+<action name="CMAPI_Autosignin">
+  <owner>vasilii@chromium.org</owner>
+  <description>Try to automatically sign user in</description>
+</action>
+
+<action name="CMAPI_Get_EmptyStore">
+  <owner>vasilii@chromium.org</owner>
+  <description>
+    A site requested a credential but the store is empty
+  </description>
+</action>
+
 <action name="CanCommitURL_BlockedAndKilled">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
   <obsolete>
     Deprecated 3/2015. Replaced by the histogram
     Stability.BadMessageTerminate.Content.
   </obsolete>
 </action>
 
 <action name="Cancel">
@@ skipping 9796 matching lines @@
 <action name="Panel_Minimize_Caption_Click">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="Panel_Minimize_Caption_Gesture">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="PasswordManager_Autofilled">
+  <owner>vasilii@chromium.org</owner>
+  <description>Username/password were autofilled</description>
+</action>
+
+<action name="PasswordManager_Choose">
+  <owner>vasilii@chromium.org</owner>
+  <description>
+    User chose a different username from the existing credentials

[Ilya Sherman, 2016/06/30 21:11:35]

This summary is not very clear to me, even as someone who's worked on the
password manager (but several years ago).  Please write a few sentences here to
clearly explain what context the user is in when making this choice.  Is a
username already filled into the form?  Did the user click to get a dropdown of
alternate usernames and choose one?  What if the user just types over the
autofilled username, and matches an existing username?  What if the user starts
typing, then sees a popup, and chooses from it?  (I'm not sure whether I'm even
on track, i.e. describing roughly the correct interaction pattern.  But
hopefully you get my meaning nonetheless.)

Please also take a closer look at the descriptions for the other actions you're
adding, and clarify them, as needed, as well.

[vasilii, 2016/07/01 12:58:59]

Done.

+  </description>
+</action>
+
+<action name="PasswordManager_ChoosePSL">
+  <owner>vasilii@chromium.org</owner>
+  <description>User chose a PSL credential from the list</description>
+</action>
+
 <action name="PasswordManager_Disabled">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="PasswordManager_Enabled">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="PasswordManager_OverridePassword">
+  <owner>vasilii@chromium.org</owner>
+  <description>User overwrote the stored password</description>
+</action>
+
+<action name="PasswordManager_OverrideUsernameAndPassword">
+  <owner>vasilii@chromium.org</owner>
+  <description>User typed new credential</description>
+</action>
+
 <action name="PasswordManager_RemovePasswordException">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
 <action name="PasswordManager_RemoveSavedPassword">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="PasswordManager_SubmitFailed">
+  <owner>vasilii@chromium.org</owner>
+  <description>Password form submission failed</description>
+</action>
+
+<action name="PasswordManager_SubmitPassed">
+  <owner>vasilii@chromium.org</owner>
+  <description>Password form submitted successfully</description>
+</action>
+
 <action name="PasswordManager_SyncCredentialShown">
   <owner>gcasto@chromium.org</owner>
   <owner>vabr@chromium.org</owner>
   <description>
     Counts the number of times a user views the saved credentials for their sync
     account.
   </description>
 </action>
 
 <action name="PasswordManager_SyncCredentialUsed">
@@ skipping 2757 matching lines @@
 <action name="webapps.AddShortcut.Manifest">
   <owner>mlamouri@chromium.org</owner>
   <description>
     Shortcut added to the homescreen with a valid Manifest. This action will be
     recorded in addition to AppShortcut, AppShortcutApple and Bookmark actions
     to keep a trend of whether the webapp also add meta tags.
   </description>
 </action>
 
 </actions>