Add Expect-CT header parsing

net/http/http_security_headers.h

Index: net/http/http_security_headers.h
diff --git a/net/http/http_security_headers.h b/net/http/http_security_headers.h
index 34f37b9f9213bc51ba69d5fd707878d694b06e5d..9c63798781c41ed1ffd921f5efc17d0deecebe79 100644
--- a/net/http/http_security_headers.h
+++ b/net/http/http_security_headers.h
@@ -24,6 +24,10 @@ const uint32_t kMaxHSTSAgeSecs = 86400 * 365;  // 1 year
 // http://tools.ietf.org/html/rfc7469#section-4.1
 const uint32_t kMaxHPKPAgeSecs = 86400 * 60;  // 60 days
 
+// https://tools.ietf.org/html/draft-ietf-httpbis-expect-ct-00 suggests a
+// conservative maximum max-age, at least while Expect-CT is new.
+const uint32_t kMaxExpectCTAgeSecs = 86400 * 30;  // 30 days
+
 // Parses |value| as a Strict-Transport-Security header value. If successful,
 // returns true and sets |*max_age| and |*include_subdomains|.
 // Otherwise returns false and leaves the output parameters unchanged.
@@ -79,6 +83,22 @@ bool NET_EXPORT_PRIVATE ParseHPKPReportOnlyHeader(const std::string& value,
                                                   bool* include_subdomains,
                                                   HashValueVector* hashes,
                                                   GURL* report_uri);
+
+// Parses |value| as an Expect-CT header value. If successful, returns true and
+// populates the |*max_age|, |*enforce|, and |*report_uri| values. Otherwise
+// returns false and leaves the output parameters unchanged.
+//
+// |value| is the right-hand side of:
+// "Expect-CT" ":"
+//     "max-age" "=" delta-seconds
+//     [ "," "enforce" ]
+//     [ "," "report-uri" "=" uri-reference ]
+//
+bool NET_EXPORT_PRIVATE ParseExpectCTHeader(const std::string& value,
+                                            base::TimeDelta* max_age,
+                                            bool* enforce,
+                                            GURL* report_uri);
+
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_SECURITY_HEADERS_H_