[ObjC ARC] Converts ios/web:ios_web_web_state_unittests to ARC.

ios/web/web_state/wk_web_view_security_util_unittest.mm

Index: ios/web/web_state/wk_web_view_security_util_unittest.mm
diff --git a/ios/web/web_state/wk_web_view_security_util_unittest.mm b/ios/web/web_state/wk_web_view_security_util_unittest.mm
index d7d77d36ad9c035ae5afc5391a08023548a41b0d..d9ca55a9913efc19d1946ecb24518fc30e30dda2 100644
--- a/ios/web/web_state/wk_web_view_security_util_unittest.mm
+++ b/ios/web/web_state/wk_web_view_security_util_unittest.mm
@@ -9,6 +9,7 @@
 
 #include <memory>
 
+#include "base/mac/foundation_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "crypto/rsa_private_key.h"
 #include "net/cert/x509_cert_types.h"
@@ -20,6 +21,10 @@
 #import "testing/gtest_mac.h"
 #include "testing/platform_test.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace web {
 namespace {
 // Subject for testing self-signed certificate.
@@ -42,8 +47,7 @@ NSArray* MakeTestCertChain(const std::string& subject) {
           reinterpret_cast<const uint8_t*>(der_cert.data()), der_cert.size()));
   if (!cert)
     return nullptr;
-  NSArray* result = @[ reinterpret_cast<id>(cert.get()) ];
-  return result;
+  return @[ (__bridge id)cert.get() ];
 }
 
 // Returns an autoreleased dictionary, which represents NSError's user info for
@@ -58,7 +62,8 @@ NSDictionary* MakeTestSSLCertErrorUserInfo() {
 base::ScopedCFTypeRef<SecTrustRef> CreateTestTrust(NSArray* cert_chain) {
   base::ScopedCFTypeRef<SecPolicyRef> policy(SecPolicyCreateBasicX509());
   SecTrustRef trust = nullptr;
-  SecTrustCreateWithCertificates(cert_chain, policy, &trust);
+  SecTrustCreateWithCertificates(base::mac::NSToCFCast(cert_chain), policy,
+                                 &trust);
   return base::ScopedCFTypeRef<SecTrustRef>(trust);
 }