Do not emit indexed header fields first in HpackEncoder.

net/spdy/hpack_round_trip_test.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cmath>
 #include <ctime>
 #include <map>
 #include <string>
 #include <vector>
 
@@ skipping 85 matching lines @@
     headers["cookie"] = "baz=bing; foo=bar";
     EXPECT_TRUE(RoundTrip(headers));
   }
   {
     map<string, string> headers;
     headers[":authority"] = "www.example.com";
     headers[":method"] = "GET";
     headers[":path"] = "/";
     headers[":scheme"] = "http";
     headers["cache-control"] = "no-cache";
-    headers["cookie"] = "foo=bar; fizzle=fazzle";
+    headers["cookie"] = "foo=bar; spam=eggs";
     EXPECT_TRUE(RoundTrip(headers));
   }
   {
     map<string, string> headers;
     headers[":authority"] = "www.example.com";
     headers[":method"] = "GET";
     headers[":path"] = "/index.html";
     headers[":scheme"] = "https";
     headers["custom-key"] = "custom-value";
     headers["cookie"] = "baz=bing; fizzle=fazzle; garbage";
@@ skipping 56 matching lines @@
       }
       headers[name] = value;
     }
     EXPECT_TRUE(RoundTrip(headers));
   }
 }
 
 }  // namespace
 
 }  // namespace net