Refactor Pickle Read methods to use higher performance PickleIterator.

ipc/param_traits_macros.h

Index: ipc/param_traits_macros.h
diff --git a/ipc/param_traits_macros.h b/ipc/param_traits_macros.h
index 05ce403cc042f50aff565209e22132ec4b7b0d9c..83a2673007b4c408de57a098f6d256e1c20e0d81 100644
--- a/ipc/param_traits_macros.h
+++ b/ipc/param_traits_macros.h
@@ -14,7 +14,7 @@
     struct IPC_MESSAGE_EXPORT ParamTraits<struct_name> { \
       typedef struct_name param_type; \
       static void Write(Message* m, const param_type& p); \
-      static bool Read(const Message* m, void** iter, param_type* p); \
+      static bool Read(const Message* m, PickleReader* iter, param_type* p); \
       static void Log(const param_type& p, std::string* l); \
     }; \
   }
@@ -30,7 +30,7 @@
     struct IPC_MESSAGE_EXPORT ParamTraits<enum_name> { \
       typedef enum_name param_type; \
       static void Write(Message* m, const param_type& p); \
-      static bool Read(const Message* m, void** iter, param_type* p); \
+      static bool Read(const Message* m, PickleReader* iter, param_type* p); \
       static void Log(const param_type& p, std::string* l); \
     }; \
   }