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

net/base/host_mapping_rules.h

Index: net/base/host_mapping_rules.h
diff --git a/net/base/host_mapping_rules.h b/net/base/host_mapping_rules.h
index 9ab06fec2cefcb83f132116dbab49676ee89f841..05f531f44732971eea3e62bdd89608330167bd3a 100644
--- a/net/base/host_mapping_rules.h
+++ b/net/base/host_mapping_rules.h
@@ -17,6 +17,7 @@ class HostPortPair;
 class HostMappingRules {
  public:
   HostMappingRules();
+  ~HostMappingRules();
 
   // Modifies |*host_port| based on the current rules. Returns true if the
   // RequestInfo was modified, false otherwise.
@@ -36,17 +37,8 @@ class HostMappingRules {
   void SetRulesFromString(const std::string& rules_string);
 
  private:
-  struct MapRule {
-    MapRule() : replacement_port(-1) {}
-
-    std::string hostname_pattern;
-    std::string replacement_hostname;
-    int replacement_port;
-  };
-
-  struct ExclusionRule {
-    std::string hostname_pattern;
-  };
+  struct MapRule;
+  struct ExclusionRule;
 
   typedef std::vector<MapRule> MapRuleList;
   typedef std::vector<ExclusionRule> ExclusionRuleList;