[Do not commit] Track revocations in content_settings::Observer

chrome/browser/permissions/permission_manager.cc

Index: chrome/browser/permissions/permission_manager.cc
diff --git a/chrome/browser/permissions/permission_manager.cc b/chrome/browser/permissions/permission_manager.cc
index c1a719a45241bd34562014df15d8fad512357426..3dfdc0ab73a4226f91e7bea146034c3d738e9662 100644
--- a/chrome/browser/permissions/permission_manager.cc
+++ b/chrome/browser/permissions/permission_manager.cc
@@ -12,6 +12,7 @@
 #include "chrome/browser/permissions/permission_context.h"
 #include "chrome/browser/permissions/permission_context_base.h"
 #include "chrome/browser/permissions/permission_request_id.h"
+#include "chrome/browser/permissions/permission_uma_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_util.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
@@ -198,6 +199,7 @@ struct PermissionManager::Subscription {
 PermissionManager::PermissionManager(Profile* profile)
     : profile_(profile),
       weak_ptr_factory_(this) {
+  HostContentSettingsMapFactory::GetForProfile(profile_)->AddObserver(this);
 }
 
 PermissionManager::~PermissionManager() {
@@ -351,8 +353,6 @@ int PermissionManager::SubscribePermissionStatusChange(
     const GURL& requesting_origin,
     const GURL& embedding_origin,
     const base::Callback<void(PermissionStatus)>& callback) {
-  if (subscriptions_.IsEmpty())
-    HostContentSettingsMapFactory::GetForProfile(profile_)->AddObserver(this);
 
   Subscription* subscription = new Subscription();
   subscription->permission = permission;
@@ -375,10 +375,6 @@ int PermissionManager::SubscribePermissionStatusChange(
 void PermissionManager::UnsubscribePermissionStatusChange(int subscription_id) {
   // Whether |subscription_id| is known will be checked by the Remove() call.
   subscriptions_.Remove(subscription_id);
-
-  if (subscriptions_.IsEmpty())
-    HostContentSettingsMapFactory::GetForProfile(profile_)
-        ->RemoveObserver(this);
 }
 
 bool PermissionManager::IsPermissionBubbleManagerMissing(
@@ -392,9 +388,14 @@ void PermissionManager::OnContentSettingChanged(
     const ContentSettingsPattern& primary_pattern,
     const ContentSettingsPattern& secondary_pattern,
     ContentSettingsType content_type,
+    ContentSetting previous_value,
     std::string resource_identifier) {
   std::list<base::Closure> callbacks;
 
+  PermissionUmaUtil::OnContentsettingChanged(profile_, primary_pattern,
+                                             secondary_pattern, content_type,
+                                             previous_value);
+
   for (SubscriptionsMap::iterator iter(&subscriptions_);
        !iter.IsAtEnd(); iter.Advance()) {
     Subscription* subscription = iter.GetCurrentValue();