Add metrics for supervised user whitelist installation and uninstallation, and absolute count.

BUG=436459

Review URL: https://codereview.chromium.org/905763002

Cr-Commit-Position: refs/heads/master@{#315235}

chrome/browser/supervised_user/supervised_user_whitelist_service.cc

@@ -9,6 +9,8 @@
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/metrics/histogram.h"
+#include "base/metrics/user_metrics.h"
+#include "base/metrics/user_metrics_action.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/scoped_user_pref_update.h"
 #include "base/strings/string_split.h"
@@ -61,6 +63,7 @@ void SupervisedUserWhitelistService::Init() {
     bool new_installation = false;
     RegisterWhitelist(it.key(), name, new_installation);
   }
+  UMA_HISTOGRAM_COUNTS_100("ManagedUsers.Whitelist.Count", whitelists->size());
 
   // Register whitelists specified on the command line.
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
@@ -257,6 +260,8 @@ syncer::SyncError SupervisedUserWhitelistService::ProcessSyncChanges(
 void SupervisedUserWhitelistService::AddNewWhitelist(
     base::DictionaryValue* pref_dict,
     const sync_pb::ManagedUserWhitelistSpecifics& whitelist) {
+  base::RecordAction(base::UserMetricsAction("ManagedUsers_Whitelist_Added"));
+
   bool new_installation = true;
   RegisterWhitelist(whitelist.id(), whitelist.name(), new_installation);
   scoped_ptr<base::DictionaryValue> dict(new base::DictionaryValue);
@@ -273,6 +278,8 @@ void SupervisedUserWhitelistService::SetWhitelistProperties(
 void SupervisedUserWhitelistService::RemoveWhitelist(
     base::DictionaryValue* pref_dict,
     const std::string& id) {
+  base::RecordAction(base::UserMetricsAction("ManagedUsers_Whitelist_Removed"));
+
   pref_dict->RemoveWithoutPathExpansion(id, NULL);
   installer_->UnregisterWhitelist(id);
   UnloadWhitelist(id);

tools/metrics/actions/actions.xml

@@ -7113,6 +7113,24 @@ should be able to be added at any place in this file.
   <description>Please enter the description of this user action.</description>
 </action>
 
+<action name="ManagedUsers_Whitelist_Added">
+  <owner>bauerb@chromium.org</owner>
+  <owner>treib@chromium.org</owner>
+  <owner>pam@chromium.org</owner>
+  <description>
+    A new whitelist has been installed for a supervised user.
+  </description>
+</action>
+
+<action name="ManagedUsers_Whitelist_Removed">
+  <owner>bauerb@chromium.org</owner>
+  <owner>treib@chromium.org</owner>
+  <owner>pam@chromium.org</owner>
+  <description>
+    A whitelist has been uninstalled for a supervised user.
+  </description>
+</action>
+
 <action name="MaxButton_Clk_ExitFS">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <description>Please enter the description of this user action.</description>

tools/metrics/histograms/histograms.xml

@@ -12314,6 +12314,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="ManagedUsers.Whitelist.Count" units="whitelists">
+  <owner>bauerb@chromium.org</owner>
+  <owner>treib@chromium.org</owner>
+  <owner>pam@chromium.org</owner>
+  <summary>
+    The number of whitelists installed for a supervised user. Recorded at every
+    profile startup.
+  </summary>
+</histogram>
+
 <histogram name="ManagedUsers.Whitelist.JsonParseDuration" units="milliseconds">
   <owner>bauerb@chromium.org</owner>
   <owner>treib@chromium.org</owner>