Move allocation of static API handles Dart_True, etc.

runtime/vm/dart.h

Index: runtime/vm/dart.h
diff --git a/runtime/vm/dart.h b/runtime/vm/dart.h
index a3234ca6324c9ab5c942a0f47a47228957d1d040..6d8cce1e4971da4c8cf7f849efeeba9d79c5fa75 100644
--- a/runtime/vm/dart.h
+++ b/runtime/vm/dart.h
@@ -13,6 +13,7 @@ namespace dart {
 // Forward declarations.
 class DebugInfo;
 class Isolate;
+class LocalHandle;
 class RawError;
 class ReadOnlyHandles;
 class ThreadPool;
@@ -46,6 +47,8 @@ class Dart : public AllStatic {
   }
   static DebugInfo* pprof_symbol_generator() { return pprof_symbol_generator_; }
 
+  static LocalHandle* AllocateReadOnlyApiHandle();
+
   static uword AllocateReadOnlyHandle();
   static bool IsReadOnlyHandle(uword address);