Revert of Make IP Address related functions return the empty string when used on an invalid address.

net/base/ip_address_number.cc

Index: net/base/ip_address_number.cc
diff --git a/net/base/ip_address_number.cc b/net/base/ip_address_number.cc
index 07fb792d8b31b43cc972fb565a027761ba9d7f3d..1e44b7d3b1ebcc74873fa762eb0ced94411c188d 100644
--- a/net/base/ip_address_number.cc
+++ b/net/base/ip_address_number.cc
@@ -103,7 +103,7 @@
   } else if (address_len == kIPv6AddressSize) {
     url::AppendIPv6Address(address, &output);
   } else {
-    return std::string();
+    CHECK(false) << "Invalid IP address with length: " << address_len;
   }
 
   output.Complete();
@@ -114,8 +114,6 @@
                                       size_t address_len,
                                       uint16_t port) {
   std::string address_str = IPAddressToString(address, address_len);
-  if (address_str.empty())
-    return address_str;
 
   if (address_len == kIPv6AddressSize) {
     // Need to bracket IPv6 addresses since they contain colons.