Revert of Reduce buggy usage of the registry controlled domain service.

url/url_canon.h

Index: url/url_canon.h
diff --git a/url/url_canon.h b/url/url_canon.h
index c4852e490b05b0286b463ab23eca0c238eeec52a..95d53453f64362efc98d8141c11691573eaae165 100644
--- a/url/url_canon.h
+++ b/url/url_canon.h
@@ -378,33 +378,6 @@
                                         const Component& host,
                                         CanonOutput* output,
                                         CanonHostInfo* host_info);
-
-// Canonicalizes a string according to the host canonicalization rules. Unlike
-// CanonicalizeHost, this will not check for IP addresses which can change the
-// meaning (and canonicalization) of the components. This means it is possible
-// to call this for sub-components of a host name without corruption.
-//
-// As an example, "01.02.03.04.com" is a canonical hostname. If you called
-// CanonicalizeHost on the substring "01.02.03.04" it will get "fixed" to
-// "1.2.3.4" which will produce an invalid host name when reassembled. This
-// can happen more than one might think because all numbers by themselves are
-// considered IP addresses; so "5" canonicalizes to "0.0.0.5".
-//
-// Be careful: Because Punycode works on each dot-separated substring as a
-// unit, you should only pass this function substrings that represent complete
-// dot-separated subcomponents of the original host. Even if you have ASCII
-// input, percent-escaped characters will have different meanings if split in
-// the middle.
-//
-// Returns true if the host was valid. This function will treat a 0-length
-// host as valid (because it's designed to be used for substrings) while the
-// full version above will mark empty hosts as broken.
-URL_EXPORT bool CanonicalizeHostSubstring(const char* spec,
-                                          const Component& host,
-                                          CanonOutput* output);
-URL_EXPORT bool CanonicalizeHostSubstring(const base::char16* spec,
-                                          const Component& host,
-                                          CanonOutput* output);
 
 // IP addresses.
 //