Write our JS blobs for handling native classes in Dart.

frog/leg/native_handler.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library('native');
 #import('../../lib/uri/uri.dart');
 #import('leg.dart');
 #import('elements/elements.dart');
 #import('scanner/scannerlib.dart');
 #import('ssa/ssa.dart');
@@ skipping 12 matching lines @@
   for (Type type in cls.allSupertypes) {
     List<Element> subtypes = emitter.subtypes.putIfAbsent(
         type.element,
         () => <ClassElement>[]);
     subtypes.add(cls);
   }
 }
 
 void processNativeClassesInLibrary(Compiler compiler,
                                    LibraryElement library) {
+  bool hasNativeClass = false;
   for (Link<Element> link = library.topLevelElements;
        !link.isEmpty(); link = link.tail) {
     Element element = link.head;
     if (element.kind == ElementKind.CLASS) {
       ClassElement classElement = element;
       if (classElement.isNative()) {
+        hasNativeClass = true;
         compiler.registerInstantiatedClass(classElement);
         // Also parse the node to know all its methods because
         // otherwise it will only be parsed if there is a call to
         // one of its constructor.
         classElement.parseNode(compiler);
         // Resolve to setup the inheritance.
         classElement.ensureResolved(compiler);
         // Add the information that this class is a subtype of
         // its supertypes. The code emitter and the ssa builder use that
         // information.
         NativeEmitter emitter = compiler.emitter.nativeEmitter;
         addSubtypes(classElement, emitter);
       }
     }
   }
+  if (hasNativeClass) {
+    compiler.registerStaticUse(compiler.findHelper(
+        const SourceString('dynamicFunction')));
+    compiler.registerStaticUse(compiler.findHelper(
+        const SourceString('dynamicSetMetadata')));
+  }
 }
 
 void maybeEnableNative(Compiler compiler,
                        LibraryElement library,
                        Uri uri) {
   String libraryName = uri.toString();
   if (library.script.name.contains('dart/frog/tests/native/src')
       || libraryName == 'dart:dom'
       || libraryName == 'dart:isolate'
       || libraryName == 'dart:html') {
@@ skipping 266 matching lines @@
             const LiteralDartString('void'),
             <HInstruction>[jsClosure]));
       }
     });
     LiteralString jsCode = node.arguments.head;
     builder.push(new HForeign(jsCode.dartString,
                               const LiteralDartString('Object'),
                               <HInstruction>[]));
   }
 }