Add chrome.hid.getUserSelectedDevices API.

chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/extensions/device_permissions_dialog_controller.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/thread_task_runner_handle.h"
 #include "chrome/browser/extensions/api/chrome_device_permissions_prompt.h"
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_sheet.h"
 #import "chrome/browser/ui/cocoa/constrained_window/constrained_window_custom_window.h"
 #import "chrome/browser/ui/cocoa/extensions/device_permissions_view_controller.h"
+#include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "device/usb/usb_device.h"
 
 using extensions::DevicePermissionsPrompt;
 
 DevicePermissionsDialogController::DevicePermissionsDialogController(
     content::WebContents* web_contents,
     scoped_refptr<DevicePermissionsPrompt::Prompt> prompt)
     : prompt_(prompt) {
   view_controller_.reset(
       [[DevicePermissionsViewController alloc] initWithController:this
@@ skipping 23 matching lines @@
   [view_controller_ devicesChanged];
 }
 
 void DevicePermissionsDialogController::OnConstrainedWindowClosed(
     ConstrainedWindowMac* window) {
   prompt_->Dismissed();
   base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, this);
 }
 
 void ChromeDevicePermissionsPrompt::ShowDialog() {
-  // These objects will delete themselves when the dialog closes.
-  new DevicePermissionsDialogController(web_contents(), prompt());
+  web_modal::WebContentsModalDialogManager* manager =
+      web_modal::WebContentsModalDialogManager::FromWebContents(web_contents());
+  if (manager) {
+    // These objects will delete themselves when the dialog closes.
+    new DevicePermissionsDialogController(web_contents(), prompt());
+  } else {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE,
+        base::Bind(&DevicePermissionsPrompt::Prompt::Dismissed, prompt()));
+  }
 }