Add a global on/off switch for content settings and expose a toggle on the Website Settings options…

chrome/browser/content_settings/content_settings_override_provider.cc

Index: chrome/browser/content_settings/content_settings_override_provider.cc
diff --git a/chrome/browser/content_settings/content_settings_override_provider.cc b/chrome/browser/content_settings/content_settings_override_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8e34c8f3a9dbf31e8fde51564da2b86baedf8da9
--- /dev/null
+++ b/chrome/browser/content_settings/content_settings_override_provider.cc
@@ -0,0 +1,91 @@
+// Copyright 2014 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_override_provider.h"
+
+#include <string>
+
+#include "base/auto_reset.h"
+#include "base/prefs/pref_service.h"
+#include "base/prefs/scoped_user_pref_update.h"
+#include "base/values.h"
+#include "chrome/browser/content_settings/content_settings_utils.h"
+#include "chrome/common/content_settings.h"
+#include "chrome/common/pref_names.h"
+#include "components/pref_registry/pref_registry_syncable.h"
+#include "content/public/browser/browser_thread.h"
+
+using content::BrowserThread;
+
+namespace content_settings {
+
+// static
+void OverrideProvider::RegisterProfilePrefs(
+    user_prefs::PrefRegistrySyncable* registry) {
+  registry->RegisterDictionaryPref(
+      prefs::kOverrideContentSettings,
+      user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
+}
+
+OverrideProvider::OverrideProvider(PrefService* prefs, bool incognito)
+    : prefs_(prefs), is_incognito_(incognito) {
+  DCHECK(prefs_);
+
+  // Read global overrides.
+  ReadOverrideSettings();
+}
+
+OverrideProvider::~OverrideProvider() {
+}
+
+void OverrideProvider::SetContentSetting(ContentSettingsType content_type,
+                                         bool is_enabled) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

[Bernhard Bauer, 2014/09/10 17:44:53]

There is a DCHECK_CURRENTLY_ON macro that will give more informative error
messages on failure.

[Daniel Nishi, 2014/09/10 23:30:20]

Done.

+  DCHECK(prefs_);
+
+  if (is_incognito_)
+    return;
+
+  DictionaryPrefUpdate update(prefs_, prefs::kOverrideContentSettings);
+  base::DictionaryValue* default_settings_dictionary = update.Get();
+  base::AutoLock lock(lock_);
+  override_settings_[content_type] = is_enabled;
+  default_settings_dictionary->SetWithoutPathExpansion(
+      GetTypeName(content_type), new base::FundamentalValue(is_enabled));
+}
+
+bool OverrideProvider::IsEnabled(ContentSettingsType content_type) const {
+  base::AutoLock lock(lock_);
+  std::map<ContentSettingsType, bool>::const_iterator it =
+      override_settings_.find(content_type);
+  if (it == override_settings_.end())
+    return true;
+
+  return it->second;
+}
+
+void OverrideProvider::ReadOverrideSettings() {
+  const base::DictionaryValue* override_settings_dictionary =

[Bernhard Bauer, 2014/09/10 17:44:54]

I would DCHECK that you're on the UI thread here. PrefService will do that as
well, but if you're checking it in other places in this class, doing it here as
well would be consistent.

[Daniel Nishi, 2014/09/10 23:30:21]

Done.

+      prefs_->GetDictionary(prefs::kOverrideContentSettings);
+
+  override_settings_.clear();
+
+  if (override_settings_dictionary) {
+    for (base::DictionaryValue::Iterator i(*override_settings_dictionary);
+         !i.IsAtEnd();
+         i.Advance()) {
+      const std::string& content_type(i.key());
+      for (size_t type = 0; type < CONTENT_SETTINGS_NUM_TYPES; ++type) {
+        if (content_type == GetTypeName(ContentSettingsType(type))) {
+          bool bool_value = true;
+          bool rv = i.value().GetAsBoolean(&bool_value);
+          DCHECK(rv);
+          override_settings_[ContentSettingsType(type)] = bool_value;
+          break;
+        }
+      }
+    }
+  }
+}
+}  // namespace content_settings