Correct iOS build for latest Xcode beta.

ios/web/web_state/ui/crw_web_controller_unittest.mm

 // Copyright 2012 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.
 
 #import "ios/web/web_state/ui/crw_web_controller.h"
 
 #import <UIKit/UIKit.h>
 #import <WebKit/WebKit.h>
 
 #include "base/mac/scoped_nsobject.h"
@@ skipping 821 matching lines @@
 // correct arguments if WKWebView fails to load a page with bad SSL cert.
 TEST_F(CRWWKWebViewWebControllerTest, SSLError) {
   CR_TEST_REQUIRES_WK_WEB_VIEW();
 
   ASSERT_FALSE([mockDelegate_ SSLInfo].is_valid());
 
   NSError* error =
       [NSError errorWithDomain:NSURLErrorDomain
                           code:NSURLErrorServerCertificateHasUnknownRoot
                       userInfo:nil];
-  [static_cast<id<WKNavigationDelegate>>(webController_.get()) webView:nil
+  WKWebView* webView = static_cast<WKWebView*>([webController_ webView]);
+  [static_cast<id<WKNavigationDelegate>>(webController_.get()) webView:webView
                                           didFailProvisionalNavigation:nil
                                                              withError:error];
 
   // Verify correctness of delegate's method arguments.
   EXPECT_TRUE([mockDelegate_ SSLInfo].is_valid());
   EXPECT_EQ(net::CERT_STATUS_INVALID, [mockDelegate_ SSLInfo].cert_status);
   EXPECT_EQ(net::CERT_STATUS_INVALID, [mockDelegate_ SSLStatus].cert_status);
   EXPECT_EQ(web::SECURITY_STYLE_AUTHENTICATION_BROKEN,
             [mockDelegate_ SSLStatus].security_style);
   EXPECT_FALSE([mockDelegate_ recoverable]);
@@ skipping 622 matching lines @@
                    // https://bugs.webkit.org/show_bug.cgi?id=140203
                    VLOG(1) << "Script has been flushed.";
                  }];
   // -evaluateJavaScript:stringResultHandler: is asynchronous so JavaScript
   // evaluation will not happen until TearDown, which deallocates
   // CRWWebController, which in its turn will deallocate WKWebView to create a
   // crashy condition.
 };
 
 }  // namespace