Replace the existing SpdyHeaderBlock typedef with a class.

net/quic/test_tools/quic_test_packet_maker.cc

Index: net/quic/test_tools/quic_test_packet_maker.cc
diff --git a/net/quic/test_tools/quic_test_packet_maker.cc b/net/quic/test_tools/quic_test_packet_maker.cc
index 2fa60a5fe446d716d2ad6318e48d4d493dfa1d9b..46112634463480fb977ee2d5f6497e20f9743096 100644
--- a/net/quic/test_tools/quic_test_packet_maker.cc
+++ b/net/quic/test_tools/quic_test_packet_maker.cc
@@ -260,16 +260,16 @@ SpdyHeaderBlock QuicTestPacketMaker::GetRequestHeaders(
     const std::string& path) {
   SpdyHeaderBlock headers;
   if (version_ <= QUIC_VERSION_24) {
+    headers[":version"] = "HTTP/1.1";
+  }
+  headers[":method"] = method;
+  if (version_ <= QUIC_VERSION_24) {
     headers[":host"] = host_;
   } else {
     headers[":authority"] = host_;
   }
-  headers[":path"] = path;
   headers[":scheme"] = scheme;
-  headers[":method"] = method;
-  if (version_ <= QUIC_VERSION_24) {
-    headers[":version"] = "HTTP/1.1";
-  }
+  headers[":path"] = path;
   return headers;
 }