Fix unrecoverable SSL interstitials.

Unrecoverable SSL errors were broken in 	Merge 229993, by the upstream CL:
https://codereview.chromium.org/23965003/.
This fix removes the iOS specific interstitial.mm and uses interstitial_page_impl
instead.
It also adds support for unrecoverable errors, by returning a DENIED judgment
to some errors.

BUG=310607
TEST=Go to https://test-sspev.verisign.com/. Clicking on "Revoked" should trigger an unrecoverable error, clicking on "Expired" should trigger a recoverable error (with a "proceed anyway" button)

Review URL: https://chromereviews.googleplex.com/12347017

Review URL: https://codereview.chromium.org/1469063002

Cr-Commit-Position: refs/heads/master@{#361109}

ios/provider/ios_provider_chrome.gyp

@@ -11,6 +11,8 @@
       'target_name': 'ios_provider_chrome_browser',
       'type': 'static_library',
       'sources': [
+        '../public/provider/chrome/browser/browser_constants.cc',
+        '../public/provider/chrome/browser/browser_constants.h',
         '../public/provider/chrome/browser/browser_state/chrome_browser_state.cc',
         '../public/provider/chrome/browser/browser_state/chrome_browser_state.h',
         '../public/provider/chrome/browser/browser_state/chrome_browser_state_manager.h',

ios/public/provider/chrome/browser/browser_constants.cc

+// Copyright 2013 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 "ios/public/provider/chrome/browser/browser_constants.h"
+
+namespace ios {
+
+const char kSpoofingAttemptFlag[] = "SpoofingAttempt_IOS";
+
+}  // namespace ios

ios/public/provider/chrome/browser/browser_constants.h

+// Copyright 2013 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_PUBLIC_PROVIDER_CHROME_BROWSER_BROWSER_CONSTANTS_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_BROWSER_CONSTANTS_H_
+
+namespace ios {
+
+// This string is a flag for net::SSLInfo signaling that the error is not a
+// typical certificate error, but rather is a spoofing attempt.
+// It can be used to customize the interstitial error page.
+extern const char kSpoofingAttemptFlag[];
+
+}  // namespace ios
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_BROWSER_CONSTANTS_H_