Log device/hid messages to chrome://device-log.

device/hid/hid_service.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.h"
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/stl_util.h"
+#include "components/device_event_log/device_event_log.h"
 
 #if defined(OS_LINUX) && defined(USE_UDEV)
 #include "device/hid/hid_service_linux.h"
 #elif defined(OS_MACOSX)
 #include "device/hid/hid_service_mac.h"
 #else
 #include "device/hid/hid_service_win.h"
 #endif
 
 namespace device {
@@ skipping 74 matching lines @@
 
 HidService::~HidService() {
   DCHECK(thread_checker_.CalledOnValidThread());
 }
 
 void HidService::AddDevice(scoped_refptr<HidDeviceInfo> device_info) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!ContainsKey(devices_, device_info->device_id())) {
     devices_[device_info->device_id()] = device_info;
 
+    HID_LOG(USER) << "HID device "
+                  << (enumeration_ready_ ? "added" : "detected")
+                  << ": vendorId = " << device_info->vendor_id()
+                  << ", productId = " << device_info->product_id()
+                  << ", deviceId = '" << device_info->device_id() << "'";
+
     if (enumeration_ready_) {
       FOR_EACH_OBSERVER(Observer, observer_list_, OnDeviceAdded(device_info));
     }
   }
 }
 
 void HidService::RemoveDevice(const HidDeviceId& device_id) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DeviceMap::iterator it = devices_.find(device_id);
   if (it != devices_.end()) {
+    HID_LOG(USER) << "HID device removed: deviceId = '" << device_id << "'";
+
     if (enumeration_ready_) {
       FOR_EACH_OBSERVER(Observer, observer_list_, OnDeviceRemoved(it->second));
     }
     devices_.erase(it);
   }
 }
 
 void HidService::FirstEnumerationComplete() {
   enumeration_ready_ = true;
 
   if (!pending_enumerations_.empty()) {
     std::vector<scoped_refptr<HidDeviceInfo>> devices;
     for (const auto& map_entry : devices_) {
       devices.push_back(map_entry.second);
     }
 
     for (const GetDevicesCallback& callback : pending_enumerations_) {
       callback.Run(devices);
     }
     pending_enumerations_.clear();
   }
 }
 
 }  // namespace device