Add a HostContentSettingsMap layer for Supervised Users.

components/content_settings/core/browser/content_settings_supervised_provider.cc

Index: components/content_settings/core/browser/content_settings_supervised_provider.cc
diff --git a/components/content_settings/core/browser/content_settings_supervised_provider.cc b/components/content_settings/core/browser/content_settings_supervised_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0efba2cc9bc973e32fedcc79234acb14fe49ef07
--- /dev/null
+++ b/components/content_settings/core/browser/content_settings_supervised_provider.cc
@@ -0,0 +1,145 @@
+// 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 "components/content_settings/core/browser/content_settings_supervised_provider.h"
+
+#include <string>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/json/json_reader.h"
+#include "base/prefs/pref_service.h"
+#include "base/values.h"
+#include "components/content_settings/core/browser/content_settings_binary_value_map.h"
+#include "components/content_settings/core/browser/content_settings_rule.h"
+#include "components/content_settings/core/browser/content_settings_utils.h"
+#include "components/content_settings/core/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+
+namespace {
+
+struct PrefsForSupervisedContentSettingsMapEntry {
+  const char* pref_name;
+  ContentSettingsType content_type;
+};
+
+const PrefsForSupervisedContentSettingsMapEntry
+    kPrefsForSupervisedContentSettingsMap[] = {
+  {
+    prefs::kSupervisedGeolocationDisabled,
+    CONTENT_SETTINGS_TYPE_GEOLOCATION,
+  }, {
+    prefs::kSupervisedCameraMicDisabled,
+    CONTENT_SETTINGS_TYPE_MEDIASTREAM,
+  }
+};
+
+void SetContentSettingFromPreference(
+    PrefService* prefs,
+    content_settings::BinaryValueMap& value_map,

[Bernhard Bauer, 2015/02/05 12:07:51]

Don't use non-const references. If you want to change the map, pass a pointer to
it so it's obvious.

Also, any reason why this isn't a method?

[knn, 2015/02/26 12:07:30]

Done. This isn't a method as I don't want to expose the ugly
PrefsForSupervisedContentSettingsMapEntry and the actual mapping itself.

+    const PrefsForSupervisedContentSettingsMapEntry& pref_map_entry) {
+  const PrefService::Preference* pref =
+      prefs->FindPreference(pref_map_entry.pref_name);
+  DCHECK(pref);
+  DCHECK(pref->IsManagedByCustodian());
+  bool is_disabled;
+  if (!pref->GetValue()->GetAsBoolean(&is_disabled)) {
+    NOTREACHED();
+    return;
+  }
+  value_map.SetContentSettingDisabled(pref_map_entry.content_type, is_disabled);
+}
+
+}  // namespace
+
+namespace content_settings {
+
+// static
+void SupervisedProvider::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterBooleanPref(
+      prefs::kSupervisedGeolocationDisabled, false,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  registry->RegisterBooleanPref(
+      prefs::kSupervisedCameraMicDisabled, false,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+}
+
+SupervisedProvider::SupervisedProvider(PrefService* prefs) : prefs_(prefs) {
+  ReadContentSettingsFromPreferences();
+
+  pref_change_registrar_.Init(prefs_);
+  PrefChangeRegistrar::NamedChangeCallback callback = base::Bind(
+      &SupervisedProvider::OnPreferenceChanged, base::Unretained(this));
+  pref_change_registrar_.Add(prefs::kSupervisedGeolocationDisabled, callback);
+  pref_change_registrar_.Add(prefs::kSupervisedCameraMicDisabled, callback);
+}
+
+SupervisedProvider::~SupervisedProvider() {
+  DCHECK(!prefs_);
+}
+
+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::ReadContentSettingsFromPreferences() {
+  base::AutoLock auto_lock(lock_);
+  for (const auto& pref_map_entry : kPrefsForSupervisedContentSettingsMap) {
+    if (!prefs_->HasPrefPath(pref_map_entry.pref_name)) {
+      VLOG(2) << "Skipping unset preference: " << pref_map_entry.pref_name;
+      continue;
+    }
+    SetContentSettingFromPreference(prefs_, value_map_, pref_map_entry);
+  }
+}
+
+// Since the SupervisedProvider is a read only content settings provider, all
+// methodes of the ProviderInterface that set or delete any settings do nothing.

[Bernhard Bauer, 2015/02/05 12:07:51]

Nit: "methods"

[knn, 2015/02/26 12:07:30]

Done.

+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();
+  if (!prefs_)
+    return;
+  pref_change_registrar_.RemoveAll();
+  prefs_ = NULL;

[Bernhard Bauer, 2015/02/05 12:07:51]

Use nullptr instead of NULL.

[knn, 2015/02/26 12:07:30]

Done.

+}
+
+void SupervisedProvider::OnPreferenceChanged(const std::string& name) {
+  DCHECK(CalledOnValidThread());
+  scoped_ptr<base::AutoLock> auto_lock(new base::AutoLock(lock_));

[Bernhard Bauer, 2015/02/05 12:07:51]

You can just put this into a nested scope that ends right before you call
NotifyObservers().

[knn, 2015/02/26 12:07:30]

Done.

+  bool is_valid_preference = false;
+  for (const auto& pref_map_entry : kPrefsForSupervisedContentSettingsMap) {
+    if (name == pref_map_entry.pref_name) {
+      is_valid_preference = true;
+      SetContentSettingFromPreference(prefs_, value_map_, pref_map_entry);
+      break;
+    }
+  }
+  DCHECK(is_valid_preference);
+  auto_lock.reset();
+
+  NotifyObservers(ContentSettingsPattern(), ContentSettingsPattern(),
+                  CONTENT_SETTINGS_TYPE_DEFAULT, std::string());
+}
+
+}  // namespace content_settings