Handle RTCCertificate::fromPEM returning nullptr, with a unit test.

third_party/WebKit/Source/bindings/modules/v8/serialization/V8ScriptValueDeserializerForModules.cpp

 // 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 "bindings/modules/v8/serialization/V8ScriptValueDeserializerForModules.h"
 
 #include "bindings/modules/v8/serialization/WebCryptoSubTags.h"
 #include "modules/crypto/CryptoKey.h"
 #include "modules/peerconnection/RTCCertificate.h"
 #include "public/platform/Platform.h"
@@ skipping 16 matching lines @@
       return readCryptoKey();
     case RTCCertificateTag: {
       String pemPrivateKey;
       String pemCertificate;
       if (!readUTF8String(&pemPrivateKey) || !readUTF8String(&pemCertificate))
         return nullptr;
       std::unique_ptr<WebRTCCertificateGenerator> certificateGenerator(
           Platform::current()->createRTCCertificateGenerator());
       std::unique_ptr<WebRTCCertificate> certificate =
           certificateGenerator->fromPEM(pemPrivateKey, pemCertificate);
+      if (!certificate)
+        return nullptr;
       return new RTCCertificate(std::move(certificate));
     }
     default:
       break;
   }
   return nullptr;
 }
 
 namespace {
 
@@ skipping 213 matching lines @@
   WebCryptoKey key = WebCryptoKey::createNull();
   if (!Platform::current()->crypto()->deserializeKeyForClone(
           algorithm, keyType, extractable, usages,
           reinterpret_cast<const unsigned char*>(keyData), keyDataLength, key))
     return nullptr;
 
   return CryptoKey::create(key);
 }
 
 }  // namespace blink