Updates WKWebViewSecurityUtil to handle deprecated enum values.

ios/web/web_state/wk_web_view_security_util.mm

 // Copyright 2014 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/wk_web_view_security_util.h"
 
 #include "base/mac/scoped_cftyperef.h"
 #include "base/strings/sys_string_conversions.h"
 #include "net/cert/x509_certificate.h"
 #include "net/ssl/ssl_info.h"
@@ skipping 121 matching lines @@
     case kSecTrustResultInvalid:
       return SECURITY_STYLE_UNKNOWN;
     case kSecTrustResultProceed:
     case kSecTrustResultUnspecified:
       return SECURITY_STYLE_AUTHENTICATED;
     case kSecTrustResultDeny:
     case kSecTrustResultRecoverableTrustFailure:
     case kSecTrustResultFatalTrustFailure:
     case kSecTrustResultOtherError:
       return SECURITY_STYLE_AUTHENTICATION_BROKEN;
+
+    // TODO(crbug.com/): This default clause exists because
+    // kSecTrustResultConfirm was deprecated in iOS7, but leads to a compile
+    // error if used with newer SDKs.  Remove the default clause once this
+    // switch statement successfully compiles without kSecTrustResultConfirm.
+    default:

[rohitrao (ping after 24h), 2016/06/14 15:20:32]

Eugene asked whether this should be hidden behind a preprocessor guard.  My
feeling is that the iOS9 SDK is never going to change to include new enum
values, and anything newer will have a default clause, so adding a guard doesn't
meaningfully protect us from anything.  Thoughts?

If we're ok with this approach, I'll file a bug for the TODO.

[Eugene But (OOO till 7-30), 2016/06/14 15:35:07]

I'm totally fine with having default. And I'm not even sure if we ned a TODO
here. Having a comment is fine IMO.

[sdefresne, 2016/06/14 18:03:09]

+1 to eugenebut comment.

+      NOTREACHED();
+      return SECURITY_STYLE_UNKNOWN;
   }
-  NOTREACHED();
-  return SECURITY_STYLE_UNKNOWN;
 }
 
 }  // namespace web