Reporting: Implement header parser.

net/reporting/reporting_header_parser.h

+// Copyright 2017 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 NET_REPORTING_REPORTING_HEADER_PARSER_H_
+#define NET_REPORTING_REPORTING_HEADER_PARSER_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "net/base/net_export.h"
+
+class GURL;
+
+namespace base {
+class Value;
+}  // namespace base
+
+namespace net {
+
+class ReportingCache;
+
+// Parses Report-To headers and writes the endpoint configurations to the
+// ReportingCache.
+class NET_EXPORT ReportingHeaderParser {
+ public:
+  // Parses the normalized Report-To header value |json_value| sent in response
+  // to a request for |url| at |now|, and applies the endpoint configurations
+  // to |cache|.
+  static void ParseHeader(ReportingCache* cache,
+                          base::TimeTicks now,
+                          const GURL& url,
+                          const std::string& json_value);
+
+ private:
+  // Processes a single endpoint's parsed value from the Report-To header(s).
+  // Creates, updates, or removes a client in the cache as needed.
+  //
+  // |url| is the URL that the header came from.
+  //
+  // |value| is the parsed value.
+  static void ProcessEndpoint(ReportingCache* cache,
+                              base::TimeTicks now,
+                              const GURL& url,
+                              const base::Value& value);
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ReportingHeaderParser);
+};
+
+}  // namespace net
+
+#endif  // NET_REPORTING_REPORTING_HEADER_PARSER_H_