Wire up an api to darken screen for accessibility

chrome/browser/accessibility/accessibility_extension_api.cc

 // Copyright (c) 2012 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/accessibility/accessibility_extension_api.h"
 
 #include <stddef.h>
 
 #include "base/json/json_writer.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 12 matching lines @@
 #include "content/public/browser/browser_accessibility_state.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/lazy_background_task_queue.h"
 #include "extensions/common/error_utils.h"
 #include "extensions/common/manifest_handlers/background_info.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/chromeos/ui/accessibility_focus_ring_controller.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+#include "chromeos/dbus/power_manager_client.h"
+
 using chromeos::AccessibilityFocusRingController;
 #endif
 
 namespace accessibility_private = extensions::api::accessibility_private;
 
 namespace {
 #if defined(OS_CHROMEOS)
 // ScreenRect fields.
 const char kLeft[] = "left";
 const char kTop[] = "top";
@@ skipping 79 matching lines @@
   } else {
     manager->SetKeyboardListenerExtensionId(std::string(),
                                             details.GetProfile());
     manager->set_keyboard_listener_capture(false);
   }
   return RespondNow(NoArguments());
 #endif  // defined OS_CHROMEOS
 
   return RespondNow(Error(kErrorNotSupported));
 }
+
+ExtensionFunction::ResponseAction
+AccessibilityPrivateDarkenScreenFunction::Run() {
+  ChromeExtensionFunctionDetails details(this);
+  CHECK(extension());
+
+#if defined(OS_CHROMEOS)
+  bool darken;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetBoolean(0, &darken));
+  chromeos::PowerManagerClient* client =
+      chromeos::DBusThreadManager::Get()->GetPowerManagerClient();
+
+  // Called twice to ensure the cros end of the dbus message is in a good
+  // state.
+  client->SetBacklightsForcedOff(!darken);
+  client->SetBacklightsForcedOff(darken);
+  return RespondNow(NoArguments());
+#endif  // defined OS_CHROMEOS
+
+  return RespondNow(Error(kErrorNotSupported));
+}