Fuchsia: Memory reservation and partial unmapping

runtime/vm/virtual_memory.cc

Index: runtime/vm/virtual_memory.cc
diff --git a/runtime/vm/virtual_memory.cc b/runtime/vm/virtual_memory.cc
index 1e62f8b7a380a7645ac918b88dd2c137b3c4ef30..93e3b84e08c8c17ec6baaeab7ed9482abadd43d3 100644
--- a/runtime/vm/virtual_memory.cc
+++ b/runtime/vm/virtual_memory.cc
@@ -20,7 +20,7 @@ void VirtualMemory::Truncate(intptr_t new_size, bool try_unmap) {
   ASSERT(new_size <= size());
   if (try_unmap &&
       (reserved_size_ == size()) && /* Don't create holes in reservation. */
-      FreeSubSegment(reinterpret_cast<void*>(start() + new_size),
+      FreeSubSegment(handle(), reinterpret_cast<void*>(start() + new_size),
                      size() - new_size)) {
     reserved_size_ = new_size;
   }