FBTF: Move a bunch of code to the headers and remove includes.

net/base/dnssec_chain_verifier.h

Index: net/base/dnssec_chain_verifier.h
diff --git a/net/base/dnssec_chain_verifier.h b/net/base/dnssec_chain_verifier.h
index d896c6cb36243b889888ae8b01aceed5935edced..60376c0e983cc5715ac8f42c8e994a36ce9fa75c 100644
--- a/net/base/dnssec_chain_verifier.h
+++ b/net/base/dnssec_chain_verifier.h
@@ -10,7 +10,6 @@
 #include <vector>
 
 #include "base/string_piece.h"
-#include "net/base/dnssec_keyset.h"
 
 namespace net {
 
@@ -67,14 +66,7 @@ class DNSSECChainVerifier {
                                  base::StringPiece b);
 
  private:
-  struct Zone {
-    base::StringPiece name;
-    // The number of consecutive labels which |name| shares with |target_|,
-    // counting right-to-left from the root.
-    unsigned matching_labels;
-    DNSSECKeySet trusted_keys;
-    Zone* prev;
-  };
+  struct Zone;
 
   bool U8(uint8*);
   bool U16(uint16*);