Descriptive log for HID device open failure on Linux.

device/hid/hid_service_linux.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 <linux/hidraw.h>
 #include <sys/ioctl.h>
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 96 matching lines @@
   str_property = udev_device_get_property_value(device, kHIDUnique);
   if (str_property != NULL)
     device_info.serial_number = str_property;
 
   str_property = udev_device_get_property_value(device, kHIDName);
   if (str_property != NULL)
     device_info.product_name = str_property;
 
   std::string dev_node;
   if (!FindHidrawDevNode(device, &dev_node)) {
-    LOG(ERROR) << "Cannot open HID device as hidraw device.";
+    LOG(ERROR) << "Cannot find device node for HID device.";
     return;
   }
 
   int flags = base::File::FLAG_OPEN | base::File::FLAG_READ;
 
   base::File device_file(base::FilePath(dev_node), flags);
   if (!device_file.IsValid()) {
-    LOG(ERROR) << device_file.error_details();
+    LOG(ERROR) << "Cannot open '" << dev_node << "': "
+        << base::File::ErrorToString(device_file.error_details());
     return;
   }
 
   int desc_size = 0;
   int res = ioctl(device_file.GetPlatformFile(), HIDIOCGRDESCSIZE, &desc_size);
   if (res < 0) {
     LOG(ERROR) << "HIDIOCGRDESCSIZE failed.";
     device_file.Close();
     return;
   }
@@ skipping 56 matching lines @@
         *result = raw_path;
         return true;
       }
     }
   }
 
   return false;
 }
 
 }  // namespace device