WKWebView: Do not DCHECK on invalid CertVerifierBlockAdapter::Params.

ios/web/net/cert_verifier_block_adapter.h

 // 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.
 
 #ifndef IOS_WEB_NET_CERT_VERIFIER_BLOCK_ADAPTER_H_
 #define IOS_WEB_NET_CERT_VERIFIER_BLOCK_ADAPTER_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "net/cert/cert_verifier.h"
 #include "net/log/net_log.h"
 
 namespace net {
 
 class CertVerifyResult;
 class CRLSet;
 class X509Certificate;
 
 // Provides block-based interface for net::CertVerifier.
 class CertVerifierBlockAdapter {
  public:
   CertVerifierBlockAdapter();
   // Constructs adapter with given |CertVerifier| which can not be null.
   CertVerifierBlockAdapter(scoped_ptr<CertVerifier> cert_verifier);
 
   // When the verifier is destroyed, all certificate verification requests are
   // canceled, and their completion handlers will not be called.
   ~CertVerifierBlockAdapter();
 
   // Encapsulates verification parms. |cert| and |hostname| are mandatory, the
-  // other params are optional.
+  // other params are optional. If either of mandatory arguments is null or
+  // empty then verification |CompletionHandler| will be called with
+  // ERR_INVALID_ARGUMENT status.
   struct Params {
     // Constructs Params from X509 cert and hostname, which are mandatory for
     // verification.
     Params(scoped_refptr<net::X509Certificate> cert,
            const std::string& hostname);
     ~Params();
 
     // Certificate to verify, can not be null.
     scoped_refptr<net::X509Certificate> cert;
 
@@ skipping 24 matching lines @@
  private:
   // Underlying CertVerifier.
   scoped_ptr<CertVerifier> cert_verifier_;
   // Net Log required by CertVerifier.
   BoundNetLog net_log_;
 };
 
 }  // net
 
 #endif  // IOS_WEB_NET_CERT_VERIFIER_BLOCK_ADAPTER_H_