Open HID connections asynchronously.

device/hid/hid_service_mac.cc

 // 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 "device/hid/hid_service_mac.h"
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <IOKit/hid/IOHIDDevice.h>
 
 #include <set>
@@ skipping 241 matching lines @@
       RemoveDevice(service_path);
     }
 
     // Release reference retained by AddDevices above.
     IOObjectRelease(device);
     // Release the reference retained by IOIteratorNext.
     IOObjectRelease(device);
   }
 }
 
-scoped_refptr<HidConnection> HidServiceMac::Connect(
-    const HidDeviceId& device_id) {
+void HidServiceMac::Connect(const HidDeviceId& device_id,
+                            const ConnectCallback& callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   const auto& map_entry = devices().find(device_id);
   if (map_entry == devices().end()) {
-    return NULL;
+    task_runner_->PostTask(FROM_HERE, base::Bind(callback, nullptr));
+    return;
   }
   const HidDeviceInfo& device_info = map_entry->second;
 
   io_string_t service_path;
   strncpy(service_path, device_id.c_str(), sizeof service_path);
   base::mac::ScopedIOObject<io_service_t> service(
       IORegistryEntryFromPath(kIOMasterPortDefault, service_path));
   if (!service.get()) {
     VLOG(1) << "IOService not found for path: " << device_id;
-    return NULL;
+    task_runner_->PostTask(FROM_HERE, base::Bind(callback, nullptr));
+    return;
   }
 
   base::ScopedCFTypeRef<IOHIDDeviceRef> hid_device(
       IOHIDDeviceCreate(kCFAllocatorDefault, service));
   IOReturn result = IOHIDDeviceOpen(hid_device, kIOHIDOptionsTypeNone);
   if (result != kIOReturnSuccess) {
     VLOG(1) << "Failed to open device: "
             << base::StringPrintf("0x%04x", result);
-    return NULL;
+    task_runner_->PostTask(FROM_HERE, base::Bind(callback, nullptr));
+    return;
   }
 
-  return make_scoped_refptr(new HidConnectionMac(
-      hid_device.release(), device_info, file_task_runner_));
+  task_runner_->PostTask(
+      FROM_HERE,
+      base::Bind(callback,
+                 make_scoped_refptr(new HidConnectionMac(
+                     hid_device.release(), device_info, file_task_runner_))));
 }
 
 }  // namespace device