C bindings: Implement _DeepCopy() & some unittests.

mojo/public/c/bindings/array.h

Index: mojo/public/c/bindings/array.h
diff --git a/mojo/public/c/bindings/array.h b/mojo/public/c/bindings/array.h
index 93134be53e9ad0fc53ed25e49b8e54d197b1f3dd..8c956c318194bbd65a08ce74fdb3fb43ad07cdda 100644
--- a/mojo/public/c/bindings/array.h
+++ b/mojo/public/c/bindings/array.h
@@ -114,6 +114,20 @@ MojomValidationResult MojomArray_Validate(
     uint32_t in_num_handles,
     struct MojomValidationContext* inout_context);
 
+// Creates a new copy of |in_array| using |buffer| to allocate space.
+// Recursively creates new copies of any references from |in_array|, and updates
+// the references to point to the new copies. This operation is useful if you
+// want to linearize |in_array| using the buffer backed by |buffer|. The new
+// copy of the array is returned, or NULL if there is insufficient space in the
+// buffer, in which case the buffer may be partially used.
+// |buffer|: A mojom buffer used to allocate space for the new array.
+// |in_type_desc|: Describes the pointer and handle fields of the mojom array.
+// |in_array|: The unencoded mojom array to be copied.
+struct MojomArrayHeader* MojomArray_DeepCopy(
+    struct MojomBuffer* buffer,
+    const struct MojomTypeDescriptorArray* in_type_desc,
+    const struct MojomArrayHeader* in_array);
+
 MOJO_END_EXTERN_C
 
 #endif  // MOJO_PUBLIC_C_BINDINGS_ARRAY_H_