Allow the native resolver to setup whether it needs the Dart API scope to

runtime/vm/native_arguments.h

Index: runtime/vm/native_arguments.h
===================================================================
--- runtime/vm/native_arguments.h	(revision 31283)
+++ runtime/vm/native_arguments.h	(working copy)
@@ -131,6 +131,9 @@
   static intptr_t retval_offset() {
     return OFFSET_OF(NativeArguments, retval_);
   }
+  static intptr_t AutoSetupScopeMask() {
+    return AutoSetupScopeBits::mask_in_place();
+  }
 
   static int ParameterCountForResolution(const Function& function) {
     ASSERT(function.is_native());
@@ -157,7 +160,11 @@
     if (function.IsClosureFunction()) {
       function_bits |= kClosureFunctionBit;
     }
-    return FunctionBits::update(function_bits, tag);
+    tag = FunctionBits::update(function_bits, tag);
+    if (function.IsNativeAutoSetupScope()) {
+      tag = AutoSetupScopeBits::update(1, tag);
+    }
+    return tag;
   }
 
  private:
@@ -170,9 +177,11 @@
     kArgcSize = 24,
     kFunctionBit = 24,
     kFunctionSize = 2,
+    kAutoSetupScopeBit = 26,
   };
   class ArgcBits : public BitField<int, kArgcBit, kArgcSize> {};
   class FunctionBits : public BitField<int, kFunctionBit, kFunctionSize> {};
+  class AutoSetupScopeBits : public BitField<int, kAutoSetupScopeBit, 1> {};
   friend class Api;
   friend class BootstrapNatives;
   friend class Simulator;