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

net/base/ip_address_number_unittest.cc

Index: net/base/ip_address_number_unittest.cc
diff --git a/net/base/ip_address_number_unittest.cc b/net/base/ip_address_number_unittest.cc
index 0b37bfac39ffd232911bf00e62c8d2c3ac35336d..93e6d90793762f9ab55c947d795b4f338faa1468 100644
--- a/net/base/ip_address_number_unittest.cc
+++ b/net/base/ip_address_number_unittest.cc
@@ -34,6 +34,10 @@ TEST(IpAddressNumberTest, IPAddressToString) {
 
   uint8_t addr3[16] = {0xFE, 0xDC, 0xBA, 0x98};
   EXPECT_EQ("fedc:ba98::", IPAddressToString(addr3, sizeof(addr3)));
+
+  // IPAddressToString() shouldn't crash on invalid addresses.
+  uint8_t addr4[2];

[Nico, 2016/02/17 02:27:43]

Doesn't this have to be 4 bytes? Also, should it be initialized to something?
Else this has undefined behavior

[martijnc, 2016/02/17 08:29:53]

The length of 2 bytes is correct. This tests if IPAddressToString() returns an
empty string when called with an invalid address. The contents isn't used when
the IP has invalid length.

I'll take a look why these are failing in debug builds when I get home. Should
this be reverted in the meantime?

+  EXPECT_EQ("", IPAddressToString(addr4, sizeof(addr4)));
 }
 
 TEST(IpAddressNumberTest, IPAddressToStringWithPort) {
@@ -47,6 +51,10 @@ TEST(IpAddressNumberTest, IPAddressToStringWithPort) {
   uint8_t addr3[16] = {0xFE, 0xDC, 0xBA, 0x98};
   EXPECT_EQ("[fedc:ba98::]:8080",
             IPAddressToStringWithPort(addr3, sizeof(addr3), 8080));
+
+  // IPAddressToStringWithPort() shouldn't crash on invalid addresses.
+  uint8_t addr4[2];
+  EXPECT_EQ("", IPAddressToStringWithPort(addr4, sizeof(addr4), 8080));
 }
 
 // Test that invalid IP literals fail to parse.