chore: remove pre network service classes from shell/browser/net (#19644)

* refactor: rm IOThread class

* chore: rm expose-net-observer-api.patch

* chore: rm unused shell/browser/net/ classes

* chore: mv CertVerifierClient to separate header

* chore: rm url_request_context_getter references

shell/browser/net/cert_verifier_client.cc

@@ -0,0 +1,44 @@
+// Copyright (c) 2019 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include <utility>
+
+#include "shell/browser/net/cert_verifier_client.h"
+#include "shell/common/native_mate_converters/net_converter.h"
+
+namespace electron {
+
+VerifyRequestParams::VerifyRequestParams() = default;
+
+VerifyRequestParams::~VerifyRequestParams() = default;
+
+VerifyRequestParams::VerifyRequestParams(const VerifyRequestParams&) = default;
+
+CertVerifierClient::CertVerifierClient(CertVerifyProc proc)
+    : cert_verify_proc_(proc) {}
+
+CertVerifierClient::~CertVerifierClient() = default;
+
+void CertVerifierClient::Verify(
+    int default_error,
+    const net::CertVerifyResult& default_result,
+    const scoped_refptr<net::X509Certificate>& certificate,
+    const std::string& hostname,
+    int flags,
+    const base::Optional<std::string>& ocsp_response,
+    VerifyCallback callback) {
+  VerifyRequestParams params;
+  params.hostname = hostname;
+  params.default_result = net::ErrorToString(default_error);
+  params.error_code = default_error;
+  params.certificate = certificate;
+  cert_verify_proc_.Run(
+      params,
+      base::AdaptCallbackForRepeating(base::BindOnce(
+          [](VerifyCallback callback, const net::CertVerifyResult& result,
+             int err) { std::move(callback).Run(err, result); },
+          std::move(callback), default_result)));
+}
+
+}  // namespace electron