Add API function Dart_ZoneAllocate

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
diff --git a/runtime/include/dart_api.h b/runtime/include/dart_api.h
index d09cc842f9c563c54c43b097d18e3edf1b9dccf0..91ea07c68d6c1756358af4f4e7b74e9b06dff5e2 100755
--- a/runtime/include/dart_api.h
+++ b/runtime/include/dart_api.h
@@ -1509,4 +1509,26 @@ DART_EXPORT Dart_Handle Dart_SetNativeResolver(
 DART_EXPORT void Dart_InitPprofSupport();
 DART_EXPORT void Dart_GetPprofSymbolInfo(void** buffer, int* buffer_size);
 
+// --- Misc ----
+
+/**
+ * The Dart VM uses zone allocation for temporary structures. Zones
+ * support very fast allocation of small chunks of memory. The chunks
+ * cannot be deallocated individually, but instead zones support
+ * deallocating all chunks in one fast operation.
+ *
+ * This function makes it possible for the embedder to allocate
+ * temporary data in the VMs zone allocator.
+ *
+ * Zone allocation is possible:
+ *   1. when inside a scope where local handles can be allocated
+ *   2. when processing a message from a native port.
+ *
+ * \param size Size of the memory to allocate.
+ *
+ * \return A pointer to the allocated memory. NULL if allocation
+ *   failed. Failure might due to is no current VM zone.
+ */
+DART_EXPORT uint8_t* Dart_ZoneAllocate(intptr_t size);
+
 #endif  // INCLUDE_DART_API_H_