Allocate the profiler sample buffer and zone segments with virtual memory instead of malloc.

runtime/vm/heap.cc

Index: runtime/vm/heap.cc
diff --git a/runtime/vm/heap.cc b/runtime/vm/heap.cc
index 94d702fe3b7d11e77e89d343ac896edd8cefd065..282272cc9f57504640381e4674456be9a9666eaa 100644
--- a/runtime/vm/heap.cc
+++ b/runtime/vm/heap.cc
@@ -525,9 +525,21 @@ void Heap::RegionName(Heap* heap, Space space, char* name, intptr_t name_size) {
                                (heap->isolate()->debugger_name() == NULL);
   const char* isolate_name =
       no_isolate_name ? "<unknown>" : heap->isolate()->debugger_name();
-  const char* space_name = (space == kNew) ? "newspace" : "oldspace";
-  const char* type_name = (space == kCode) ? "code" : "data";
-  OS::SNPrint(name, name_size, "%s %s %s", isolate_name, space_name, type_name);
+  const char* space_name = NULL;
+  switch (space) {
+    case kNew:
+      space_name = "newspace";
+      break;
+    case kOld:
+      space_name = "oldspace";
+      break;
+    case kCode:
+      space_name = "codespace";
+      break;
+    default:
+      UNREACHABLE();
+  }
+  OS::SNPrint(name, name_size, "dart-%s %s", space_name, isolate_name);
 }