Add SOCKS4 and SOCKS5 fuzzers.

net/BUILD.gn

Index: net/BUILD.gn
diff --git a/net/BUILD.gn b/net/BUILD.gn
index 1c9287383f0aaff27ee9fd1df84405e4327ddb25..1a69df8096235f71bf9d13debc1f34af62d4b9d3 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -1765,10 +1765,13 @@ source_set("net_fuzzer_test_support") {
 
   sources = [
     "base/fuzzer_test_support.cc",
+    "socket/fuzzed_socket.cc",
+    "socket/fuzzed_socket.h",
   ]
   deps = [
     "//base",
     "//base:i18n",
+    "//net",
   ]
 }
 
@@ -1954,3 +1957,27 @@ fuzzer_test("net_quic_crypto_framer_parse_message_fuzzer") {
     "//net",
   ]
 }
+
+fuzzer_test("net_socks_client_socket_fuzzer") {
+  sources = [
+    "socket/socks_client_socket_fuzzer.cc",
+  ]
+  deps = [
+    ":net_fuzzer_test_support",
+    ":test_support",
+    "//base",
+    "//net",
+  ]
+}
+
+fuzzer_test("net_socks5_client_socket_fuzzer") {
+  sources = [
+    "socket/socks5_client_socket_fuzzer.cc",
+  ]
+  deps = [
+    ":net_fuzzer_test_support",
+    ":test_support",
+    "//base",
+    "//net",
+  ]
+}