Web MIDI: use GetVendorName() result only if it is available

media/midi/midi_manager_win.cc

 // Copyright 2013 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 "media/midi/midi_manager_win.h"
 
 #include <windows.h>
 #include <dbt.h>
 #include <ks.h>
 #include <ksmedia.h>
@@ skipping 273 matching lines @@
     return EXTRACT_USBAUDIO_PID(&caps.ProductGuid);
   }
   static uint16 ExtractUsbProductIdIfExists(const MIDIOUTCAPS2W& caps) {
     if (!IS_COMPATIBLE_USBAUDIO_PID(&caps.ProductGuid))
       return 0;
     return EXTRACT_USBAUDIO_PID(&caps.ProductGuid);
   }
 };
 
 std::string GetManufacturerName(const MidiDeviceInfo& info) {
-  if (info.is_usb_device)
-    return device::UsbIds::GetVendorName(info.usb_vendor_id);
+  if (info.is_usb_device) {
+    const char* name = device::UsbIds::GetVendorName(info.usb_vendor_id);
+    return std::string(name ? name : "");
+  }
 
   switch (info.manufacturer_id) {
     case MM_MICROSOFT:
       return "Microsoft Corporation";
     default:
       // TODO(toyoshim): Support other manufacture IDs.  crbug.com/472341.
       return "";
   }
 }
 
@@ skipping 880 matching lines @@
   // TOOD(toyoshim): This calculation should be done when the date is actually
   // sent.
   client->AccumulateMidiBytesSent(data.size());
 }
 
 MidiManager* MidiManager::Create() {
   return new MidiManagerWin();
 }
 
 }  // namespace media