Implement chrome.systemPrivate.getIncognitoModeAvailability extension API function

chrome/browser/extensions/extension_system_api.cc

+// Copyright (c) 2011 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/extensions/extension_system_api.h"
+
+#include "base/values.h"
+
+namespace {
+
+// Maps prefs::kIncognitoModeAvailability values (0 = enabled, ...)
+// to strings exposed to extensions.
+const char* kIncognitoModeAvailabilityStrings[] = {
+  "enabled",
+  "disabled",
+  "forced"
+};
+
+}  // namespace
+
+IncognitoModeAvailabilityTransformer::IncognitoModeAvailabilityTransformer() {
+}
+
+IncognitoModeAvailabilityTransformer::~IncognitoModeAvailabilityTransformer() {
+}
+
+Value* IncognitoModeAvailabilityTransformer::ExtensionToBrowserPref(
+    const Value* extension_pref,
+    std::string* error,
+    bool* bad_message) {
+  // We do not allow extensions to modify the IncognitoModeAvailability
+  // preference. Therefore, this function is never called.
+  NOTREACHED();
+  return NULL;
+}
+
+ Value* IncognitoModeAvailabilityTransformer::BrowserToExtensionPref(
+     const Value* browser_pref) {
+  int browser_pref_value;
+  if (!browser_pref->GetAsInteger(&browser_pref_value) ||
+      browser_pref_value < 0 ||
+      browser_pref_value >=
+          static_cast<int>(arraysize(kIncognitoModeAvailabilityStrings))) {
+    return NULL;
+  }
+  return Value::CreateStringValue(
+      kIncognitoModeAvailabilityStrings[browser_pref_value]);
+}