Implement cloud policy invalidations using the invalidation service framework.

tools/metrics/histograms/histograms.xml

 <!--
 Copyright 2013 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 used to generate a comprehensive list of Chrome histograms along
 with a detailed description for each histogram.
 
@@ skipping 2386 matching lines @@
   </summary>
 </histogram>
 
 <histogram name="Enterprise.Policy" enum="EnterprisePolicyType">
   <summary>
     Events related to fetching, saving and loading user policies, and also
     device policies on ChromeOS.
   </summary>
 </histogram>
 
+<histogram name="Enterprise.PolicyInvalidations"
+    enum="EnterprisePolicyInvalidations">
+  <summary>
+    Events for counting policy invalidations received with and without payloads.
+    Invalidations indicate that a policy has been updated and should be
+    refreshed. Payloads provide context about the policy update, but may be
+    absent if dropped by the invalidation service.
+  </summary>
+</histogram>
+
 <histogram name="Enterprise.PolicyLoadStatus" enum="EnterprisePolicyLoadStatus">
   <summary>
     Load status from the policy loaders which pull policy settings from the
     underlying platform, such as Windows Group Policy.
   </summary>
 </histogram>
 
+<histogram name="Enterprise.PolicyRefresh" enum="EnterprisePolicyRefresh">
+  <summary>
+    Events measuring effectiveness of refreshing policy when invalidations are
+    received from a service. For each refresh, indicates whether the policy
+    changed, and whether the policy was invalidated at the time of the refresh.
+  </summary>
+</histogram>
+
 <histogram name="Event.CoalescedCount.Mouse">
   <summary>Number of Mouse events coalesced.</summary>
 </histogram>
 
 <histogram name="Event.CoalescedCount.Touch">
   <summary>Number of Touch events coalesced.</summary>
 </histogram>
 
 <histogram name="Event.CoalescedLatency.Mouse" units="milliseconds">
   <summary>
@@ skipping 13709 matching lines @@
   <int value="192" label="Limit device uptime by automatically rebooting"/>
   <int value="193" label="Automatically reboot after update"/>
   <int value="194" label="Public session for auto-login"/>
   <int value="195" label="Public session auto-login timer"/>
   <int value="196"
       label="Set the restriction on the fetching of the Variations seed"/>
   <int value="197" label="Idle warning delay when running on AC power"/>
   <int value="198" label="Idle warning delay when running on battery power"/>
 </enum>
 
+<enum name="EnterprisePolicyInvalidations" type="int">
+  <int value="0" label="No payload"/>
+  <int value="1" label="Payload"/>
+</enum>
+
 <enum name="EnterprisePolicyLoadStatus" type="int">
   <summary>
     Status codes produced by the policy loaders that pull policy settings from
     the platform-specific management infrastructure, such as Windows Group
     Policy.
   </summary>
   <int value="0" label="STARTED">
     Policy load attempt started. This gets logged for each policy load attempt
     to get a baseline on the number of requests, and an arbitrary number of the
     below status codes may get added in addition.
@@ skipping 11 matching lines @@
   <int value="5" label="WOW64_REDIRECTION_DISABLED">
     Trying with Wow64 redirection disabled.
   </int>
   <int value="6" label="READ_ERROR">
     Data read error, for example file reading errors.
   </int>
   <int value="7" label="TOO_BIG">Data too large to process.</int>
   <int value="8" label="PARSE_ERROR">Parse error.</int>
 </enum>
 
+<enum name="EnterprisePolicyRefresh" type="int">
+  <int value="0" label="Changed"/>
+  <int value="1" label="Changed; Invalidations disabled"/>
+  <int value="2" label="Unchanged"/>
+  <int value="3" label="Invalidated; Changed"/>
+  <int value="4" label="Invalidated; Unchanged"/>
+</enum>
+
 <enum name="EnterprisePolicyType" type="int">
   <summary>
     Result of Policy operations as defined in
     chrome/browser/policy/enterprise_metrics.h.
   </summary>
   <int value="0" label="Load Succeeded">
     A cached policy was successfully loaded from disk.
   </int>
   <int value="1" label="Load Failed">
     Reading a cached policy from disk failed.
@@ skipping 7560 matching lines @@
   <group name="Disabled" label="Neither extra webstore link is visible"/>
   <group name="FooterLink" label="Link in bottom right of footer"/>
   <group name="PlusIcon" label="Plus icon in apps page"/>
   <affected-histogram name="Extensions.AppLaunch"/>
   <affected-histogram name="NewTabPage.DefaultPageType"/>
 </fieldtrial>
 
 </fieldtrials>
 
 </histogram-configuration>