Fuchsia: Memory reservation and partial unmapping

runtime/vm/virtual_memory.h

Index: runtime/vm/virtual_memory.h
diff --git a/runtime/vm/virtual_memory.h b/runtime/vm/virtual_memory.h
index a26b8ce74a878db05e83d7ddf2d37d2715bf2b37..baa714d96b116516249b0d52242fbd87b9e287ad 100644
--- a/runtime/vm/virtual_memory.h
+++ b/runtime/vm/virtual_memory.h
@@ -73,7 +73,7 @@ class VirtualMemory {
 
   // Free a sub segment. On operating systems that support it this
   // can give back the virtual memory to the system. Returns true on success.
-  static bool FreeSubSegment(void* address, intptr_t size);
+  static bool FreeSubSegment(int32_t handle, void* address, intptr_t size);
 
   // This constructor is only used internally when reserving new virtual spaces.
   // It does not reserve any virtual address space on its own.