iOS: Avoid an unnecessary CertStatus <-> net::Error round trip

Rather than converting a net::CertStatus into a net:Error,
and then back from a net::Error into a net::CertStatus,
use the original net::CertStatus passed through the layers.

For iOS, we don't use the Chrome network stack for these
loads, and so there will only ever be an NSError and not a
net::Error.

Bug: 618799
Change-Id: Ic94c2e248e74651e78cb604421dd93c6067250be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879796
Auto-Submit: Ryan Sleevi <rsleevi@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Ryan Sleevi <rsleevi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709198}

ios/web_view/internal/web_view_web_client.mm

@@ -98,7 +98,7 @@ base::string16 WebViewWebClient::GetPluginNotSupportedText() const {
 
 void WebViewWebClient::AllowCertificateError(
     web::WebState* web_state,
-    int cert_error,
+    int net_error,
     const net::SSLInfo& ssl_info,
     const GURL& request_url,
     bool overridable,
@@ -110,10 +110,10 @@ void WebViewWebClient::AllowCertificateError(
   SEL selector = @selector
       (webView:didFailNavigationWithSSLError:overridable:decisionHandler:);
   if ([web_view.navigationDelegate respondsToSelector:selector]) {
-    CWVCertStatus cert_status = CWVCertStatusFromNetCertStatus(
-        net::MapNetErrorToCertStatus(cert_error));
+    CWVCertStatus cert_status =
+        CWVCertStatusFromNetCertStatus(ssl_info.cert_status);
     ssl_errors::ErrorInfo error_info = ssl_errors::ErrorInfo::CreateError(
-        ssl_errors::ErrorInfo::NetErrorToErrorType(cert_error),
+        ssl_errors::ErrorInfo::NetErrorToErrorType(net_error),
         ssl_info.cert.get(), request_url);
     NSString* error_description =
         base::SysUTF16ToNSString(error_info.short_description());