Fix initial USB enumeration on Linux to return all devices.

device/usb/usb_service_linux.cc

 // Copyright 2016 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/usb/usb_service_linux.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/files/file.h"
@@ skipping 230 matching lines @@
   }
 }
 
 void UsbServiceLinux::DeviceReady(scoped_refptr<UsbDeviceLinux> device,
                                   bool success) {
   DCHECK(CalledOnValidThread());
 
   bool enumeration_became_ready = false;
   if (!enumeration_ready()) {
     DCHECK_GT(first_enumeration_countdown_, 0u);
-    if (--first_enumeration_countdown_ == 0)
+    first_enumeration_countdown_--;
+    if (enumeration_ready())
       enumeration_became_ready = true;
   }
 
   // If |device| was disconnected while descriptors were being read then it
   // will have been removed from |devices_by_path_|.
   auto it = devices_by_path_.find(device->device_path());
   if (it == devices_by_path_.end()) {
     success = false;
   } else if (success) {
     DCHECK(!base::ContainsKey(devices(), device->guid()));
@@ skipping 50 matching lines @@
     result.reserve(devices().size());
     for (const auto& map_entry : devices())
       result.push_back(map_entry.second);
     for (const auto& callback : enumeration_callbacks_)
       callback.Run(result);
     enumeration_callbacks_.clear();
   }
 }
 
 }  // namespace device