C bindings pt3: Type table definitions and barebones files to get generated code to compile.

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/struct.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.");
+
+MOJO_END_EXTERN_C
+
+#endif  // MOJO_PUBLIC_C_BINDINGS_MAP_H_