Remove Windows Vista/XP specific code from net/quic.

net/quic/quic_stream_factory.cc

Index: net/quic/quic_stream_factory.cc
diff --git a/net/quic/quic_stream_factory.cc b/net/quic/quic_stream_factory.cc
index dc47332f910797692b558b1ae5d668d6a710dad7..e431d69e1d38e2f3a5625bd95f8f6d3901feb901 100644
--- a/net/quic/quic_stream_factory.cc
+++ b/net/quic/quic_stream_factory.cc
@@ -58,10 +58,6 @@
 #include "net/ssl/token_binding.h"
 #include "net/udp/udp_client_socket.h"
 
-#if defined(OS_WIN)
-#include "base/win/windows_version.h"
-#endif
-
 using std::min;
 using NetworkHandle = net::NetworkChangeNotifier::NetworkHandle;
 
@@ -104,15 +100,6 @@ void HistogramMigrationStatus(enum QuicConnectionMigrationStatus status) {
                             MIGRATION_STATUS_MAX);
 }
 
-bool IsEcdsaSupported() {
-#if defined(OS_WIN)
-  if (base::win::GetVersion() < base::win::VERSION_VISTA)
-    return false;
-#endif
-
-  return true;
-}
-
 QuicConfig InitializeQuicConfig(const QuicTagVector& connection_options,
                                 int idle_connection_timeout_seconds) {
   DCHECK_GT(idle_connection_timeout_seconds, 0);
@@ -676,8 +663,6 @@ QuicStreamFactory::QuicStreamFactory(
                         has_aes_hardware_support);
   if (has_aes_hardware_support || prefer_aes_)
     crypto_config_.PreferAesGcm();
-  if (!IsEcdsaSupported())
-    crypto_config_.DisableEcdsa();
   // When disk cache is used to store the server configs, HttpCache code calls
   // |set_quic_server_info_factory| if |quic_server_info_factory_| wasn't
   // created.