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 1e44b7d3b1ebcc74873fa762eb0ced94411c188d..07dbc56fec09729774dcab2e1593bd9fa2427dba 100644
--- a/net/base/ip_address_number.cc
+++ b/net/base/ip_address_number.cc
@@ -103,7 +103,7 @@ std::string IPAddressToString(const uint8_t* address, size_t address_len) {
   } else if (address_len == kIPv6AddressSize) {
     url::AppendIPv6Address(address, &output);
   } else {
-    CHECK(false) << "Invalid IP address with length: " << address_len;
+    return std::string();
   }
 
   output.Complete();
@@ -113,6 +113,9 @@ std::string IPAddressToString(const uint8_t* address, size_t address_len) {
 std::string IPAddressToStringWithPort(const uint8_t* address,
                                       size_t address_len,
                                       uint16_t port) {
+  if (address_len != kIPv4AddressSize && address_len != kIPv6AddressSize)

[eroman, 2016/02/16 19:48:52]

How about instead, put the following line after IPAddressToString() invocation
below:

if (address_str.empty())
  return address_str;

This way it is tied more directly to the success/failure of IPAddressToString().
This is useful in case IPAddressToString were extended to support other sizes.

[martijnc, 2016/02/16 22:02:00]

Done.

+    return std::string();
+
   std::string address_str = IPAddressToString(address, address_len);
 
   if (address_len == kIPv6AddressSize) {