C bindings: Implement _Validate(), and some pre-requisites

mojo/public/c/bindings/map.h

 // Copyright 2016 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.
 
 #ifndef MOJO_PUBLIC_C_BINDINGS_MAP_H_
 #define MOJO_PUBLIC_C_BINDINGS_MAP_H_
 
 #include <stdint.h>
 
 #include "mojo/public/c/bindings/array.h"
-#include "mojo/public/c/bindings/buffer.h"
+#include "mojo/public/c/bindings/lib/type_descriptor.h"
+#include "mojo/public/c/bindings/lib/util.h"
 #include "mojo/public/c/bindings/struct.h"
+#include "mojo/public/c/system/handle.h"
 #include "mojo/public/c/system/macros.h"
 
 MOJO_BEGIN_EXTERN_C
 
 // A mojom Map is a mojom struct with two MojomArrayHeaders: keys and values.
 // - Number of elements in keys == number of elements values.
 // - ith key corresponds to the ith value.
 struct MojomMapHeader {
   struct MojomStructHeader header;
   union MojomArrayHeaderPtr keys;
   union MojomArrayHeaderPtr values;
 };
 MOJO_STATIC_ASSERT(sizeof(struct MojomMapHeader) == 24,
                    "struct MojomMapHeader must be 24 bytes.");
 
 union MojomMapHeaderPtr {
   struct MojomMapHeader* ptr;
   uint64_t offset;
 };
 MOJO_STATIC_ASSERT(sizeof(union MojomMapHeaderPtr) == 8,
                    "MojomMapHeaderPtr must be 8 bytes.");
 
+MojomValidationResult MojomMap_Validate(
+    const struct MojomTypeDescriptorStruct* in_type_desc,
+    const struct MojomStructHeader* in_struct,
+    uint32_t in_buf_size,
+    uint32_t in_num_handles,
+    struct MojomValidationContext* inout_context);
+
 MOJO_END_EXTERN_C
 
 #endif  // MOJO_PUBLIC_C_BINDINGS_MAP_H_