Check UsbDevice string fields for null.

device/usb/usb_device_android.cc

 // Copyright 2015 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_device_android.h"
 
 #include "base/android/build_info.h"
 #include "base/android/jni_string.h"
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 17 matching lines @@
     JNIEnv* env,
     base::WeakPtr<UsbServiceAndroid> service,
     const JavaRef<jobject>& usb_device) {
   ScopedJavaLocalRef<jobject> wrapper =
       Java_ChromeUsbDevice_create(env, usb_device);
   uint16_t device_version = 0;
   if (base::android::BuildInfo::GetInstance()->sdk_int() >= 23)
     device_version = Java_ChromeUsbDevice_getDeviceVersion(env, wrapper);
   base::string16 manufacturer_string, product_string, serial_number;
   if (base::android::BuildInfo::GetInstance()->sdk_int() >= 21) {
-    manufacturer_string = ConvertJavaStringToUTF16(
-        env, Java_ChromeUsbDevice_getManufacturerName(env, wrapper));
-    product_string = ConvertJavaStringToUTF16(
-        env, Java_ChromeUsbDevice_getProductName(env, wrapper));
-    serial_number = ConvertJavaStringToUTF16(
-        env, Java_ChromeUsbDevice_getSerialNumber(env, wrapper));
+    const JavaRef<jstring>& manufacturer_jstring =

[Reilly Grant (use Gerrit), 2017/05/30 18:50:29]

These locals must be ScopedJavaLocalRef<jstring>. Using a const
JavaRef<jstring>& here is unsafe because you are holding a reference to a return
value.

[Igor Eremeev, 2017/05/31 06:50:43]

Const ref binding would've saved the day :) However, I agree that this feature
is rather exotic to use in production code, fixed.

[Igor Eremeev, 2017/05/31 06:50:43]

Done.

+        Java_ChromeUsbDevice_getManufacturerName(env, wrapper);
+    if (!manufacturer_jstring.is_null())
+      manufacturer_string = ConvertJavaStringToUTF16(env, manufacturer_jstring);
+    const JavaRef<jstring>& product_jstring =
+        Java_ChromeUsbDevice_getProductName(env, wrapper);
+    if (!product_jstring.is_null())
+      product_string = ConvertJavaStringToUTF16(env, product_jstring);
+    const JavaRef<jstring>& serial_jstring =
+        Java_ChromeUsbDevice_getSerialNumber(env, wrapper);
+    if (!serial_jstring.is_null())
+      serial_number = ConvertJavaStringToUTF16(env, serial_jstring);
   }
   return make_scoped_refptr(new UsbDeviceAndroid(
       env, service,
       0x0200,  // USB protocol version, not provided by the Android API.
       Java_ChromeUsbDevice_getDeviceClass(env, wrapper),
       Java_ChromeUsbDevice_getDeviceSubclass(env, wrapper),
       Java_ChromeUsbDevice_getDeviceProtocol(env, wrapper),
       Java_ChromeUsbDevice_getVendorId(env, wrapper),
       Java_ChromeUsbDevice_getProductId(env, wrapper), device_version,
       manufacturer_string, product_string, serial_number, wrapper));
@@ skipping 143 matching lines @@
     scoped_refptr<UsbDeviceHandle> device_handle,
     const GURL& landing_page) {
   if (landing_page.is_valid())
     webusb_landing_page_ = landing_page;
 
   device_handle->Close();
   CallRequestPermissionCallbacks(true);
 }
 
 }  // namespace device