Fuchsia: Memory reservation and partial unmapping

runtime/vm/virtual_memory_linux.cc

Index: runtime/vm/virtual_memory_linux.cc
diff --git a/runtime/vm/virtual_memory_linux.cc b/runtime/vm/virtual_memory_linux.cc
index be3655fdbe6ef7e8a8523ca0c19d9ae0e1ebd628..3c4abec3d29657c8941307df7e909d13b365ff41 100644
--- a/runtime/vm/virtual_memory_linux.cc
+++ b/runtime/vm/virtual_memory_linux.cc
@@ -59,7 +59,9 @@ VirtualMemory::~VirtualMemory() {
 }
 
 
-bool VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
+bool VirtualMemory::FreeSubSegment(int32_t handle,
+                                   void* address,
+                                   intptr_t size) {
   unmap(address, size);
   return true;
 }