Add a HostContentSettingsMap layer for Supervised Users.

chrome/browser/content_settings/content_settings_supervised_provider.cc

+// Copyright (c) 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/content_settings_supervised_provider.h"
+
+#include <string>
+#include <vector>
+
+#include "base/synchronization/lock.h"
+#include "base/values.h"
+#include "chrome/browser/supervised_user/supervised_user_constants.h"
+#include "chrome/browser/supervised_user/supervised_user_settings_service.h"
+
+namespace {
+
+struct ContentSettingsFromSupervisedSettingsEntry {
+  const char* setting_name;
+  ContentSettingsType content_type;
+};
+
+const ContentSettingsFromSupervisedSettingsEntry
+    kContentSettingsFromSupervisedSettingsMap[] = {
+  {
+    supervised_users::kGeolocationDisabled,
+    CONTENT_SETTINGS_TYPE_GEOLOCATION,
+  }, {
+    supervised_users::kCameraMicDisabled,
+    CONTENT_SETTINGS_TYPE_MEDIASTREAM,
+  }
+};
+
+}  // namespace
+
+namespace content_settings {
+
+SupervisedProvider::SupervisedProvider(
+    SupervisedUserSettingsService* supervised_user_settings_service)
+    : weak_ptr_factory_(this) {
+  supervised_user_settings_service->Subscribe(base::Bind(
+      &content_settings::SupervisedProvider::OnSupervisedSettingsAvailable,
+      weak_ptr_factory_.GetWeakPtr()));
+}
+
+RuleIterator* SupervisedProvider::GetRuleIterator(
+    ContentSettingsType content_type,
+    const ResourceIdentifier& resource_identifier,
+    bool incognito) const {
+  scoped_ptr<base::AutoLock> auto_lock(new base::AutoLock(lock_));
+  return value_map_.GetRuleIterator(content_type, resource_identifier,
+                                    auto_lock.Pass());
+}
+
+void SupervisedProvider::OnSupervisedSettingsAvailable(
+    const base::DictionaryValue* settings) {
+  if (!settings)
+    return;
+  std::vector<ContentSettingsType> to_notify;
+  // Entering locked scope to update content settings.
+  {
+    base::AutoLock auto_lock(lock_);
+    bool new_value, old_value;
+    for (const auto& entry : kContentSettingsFromSupervisedSettingsMap) {
+      if (settings->GetBoolean(entry.setting_name, &new_value)) {
+        old_value = !value_map_.IsContentSettingEnabled(entry.content_type);
+        if (new_value != old_value) {
+          to_notify.push_back(entry.content_type);
+          value_map_.SetContentSettingDisabled(entry.content_type, new_value);
+        }
+      }
+    }
+  }
+  for (const auto& notification : to_notify) {
+    NotifyObservers(ContentSettingsPattern(), ContentSettingsPattern(),
+                    notification, std::string());
+  }
+}
+
+// Since the SupervisedProvider is a read only content settings provider, all
+// methods of the ProviderInterface that set or delete any settings do nothing.
+bool SupervisedProvider::SetWebsiteSetting(
+    const ContentSettingsPattern& primary_pattern,
+    const ContentSettingsPattern& secondary_pattern,
+    ContentSettingsType content_type,
+    const ResourceIdentifier& resource_identifier,
+    base::Value* value) {
+  return false;
+}
+
+void SupervisedProvider::ClearAllContentSettingsRules(
+    ContentSettingsType content_type) {
+}
+
+void SupervisedProvider::ShutdownOnUIThread() {
+  DCHECK(CalledOnValidThread());
+  RemoveAllObservers();
+}
+
+}  // namespace content_settings