Implement PermissionService::GetNextPermissionChange.

chrome/browser/content_settings/permission_observer.cc

+// Copyright 2015 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.
+
+#include "chrome/browser/content_settings/permission_observer.h"
+
+#include "chrome/browser/content_settings/permission_context.h"
+#include "chrome/browser/content_settings/permission_context_base.h"
+#include "chrome/browser/profiles/profile.h"
+#include "components/content_settings/core/browser/host_content_settings_map.h"
+#include "url/gurl.h"
+
+struct PermissionObserver::Subscription {
+  ContentSettingsType content_type;
+  GURL requesting_origin;
+  GURL embedding_origin;
+  PermissionChangeCallback callback;
+  ContentSetting current_value;
+};
+
+PermissionObserver::PermissionObserver(Profile* profile)
+    : profile_(profile) {
+}
+
+PermissionObserver::~PermissionObserver() {
+  if (!subscriptions_.IsEmpty())
+    profile_->GetHostContentSettingsMap()->RemoveObserver(this);
+}
+
+int PermissionObserver::Subscribe(ContentSettingsType content_type,
+                                  const GURL& requesting_origin,
+                                  const GURL& embedding_origin,
+                                  const PermissionChangeCallback& callback) {
+  if (subscriptions_.IsEmpty())
+    profile_->GetHostContentSettingsMap()->AddObserver(this);
+
+  Subscription* subscription = new Subscription();
+  subscription->content_type = content_type;
+  subscription->requesting_origin = requesting_origin;
+  subscription->embedding_origin = embedding_origin;
+  subscription->callback = callback;
+  subscription->current_value = PermissionContext::Get(profile_, content_type)
+      ->GetPermissionStatus(subscription->requesting_origin,
+                            subscription->embedding_origin);
+
+  return subscriptions_.Add(subscription);
+}
+
+void PermissionObserver::Unsubscribe(int subscription_id) {
+  // Whether |subscription_id| is known will be checked by the Remove() call.
+  subscriptions_.Remove(subscription_id);
+
+  if (subscriptions_.IsEmpty())
+    profile_->GetHostContentSettingsMap()->RemoveObserver(this);
+}
+
+void PermissionObserver::OnContentSettingChanged(
+    const ContentSettingsPattern& primary_pattern,
+    const ContentSettingsPattern& secondary_pattern,
+    ContentSettingsType content_type,
+    std::string resource_identifier) {
+  for (SubscriptionsMap::iterator iter(&subscriptions_);
+       !iter.IsAtEnd(); iter.Advance()) {
+    Subscription* subscription = iter.GetCurrentValue();
+    if (subscription->content_type != content_type)
+      continue;
+
+    if (primary_pattern.IsValid() &&
+        !primary_pattern.Matches(subscription->requesting_origin))
+      continue;
+    if (secondary_pattern.IsValid() &&
+        !secondary_pattern.Matches(subscription->embedding_origin))
+      continue;
+
+    ContentSetting new_value = PermissionContext::Get(profile_, content_type)
+        ->GetPermissionStatus(subscription->requesting_origin,
+                              subscription->embedding_origin);
+    if (subscription->current_value == new_value)
+      continue;
+
+    subscription->current_value = new_value;
+    subscription->callback.Run(new_value);
+  }
+}