Implement cloud policy invalidations using the invalidation service framework.

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 482c83a13f9bb00a662c7d20eae6a527047fd294..1359c00a4984351ed2731b602ff607c4fe842c5d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -2404,6 +2404,16 @@ other types of suffix sets.
   </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
@@ -2411,6 +2421,14 @@ other types of suffix sets.
   </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>
@@ -16140,6 +16158,11 @@ other types of suffix sets.
   <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
@@ -16171,6 +16194,14 @@ other types of suffix sets.
   <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