Reduce size by emitting $.foo instead of Isolate.prototype.foo.

lib/compiler/implementation/native_emitter.dart

Index: lib/compiler/implementation/native_emitter.dart
diff --git a/lib/compiler/implementation/native_emitter.dart b/lib/compiler/implementation/native_emitter.dart
index f5a8a6db88f3822b5f53a659d3a5318441959659..3cdcb95093484e74d62b1ac44af42a429c77a180 100644
--- a/lib/compiler/implementation/native_emitter.dart
+++ b/lib/compiler/implementation/native_emitter.dart
@@ -69,12 +69,13 @@ class NativeEmitter {
     buffer.add(nativeCode);
     buffer.add(';\n');
 
+    String isolatePrototype = '${compiler.namer.ISOLATE}.prototype';
     String attachTo(name) => "$className.$name";
 
     for (Element member in classElement.members) {
       if (member.isInstanceMember()) {
         compiler.emitter.addInstanceMember(
-            member, attachTo, buffer, isNative: true);
+            member, attachTo, buffer, isolatePrototype, isNative: true);
       }
     }
   }
@@ -117,10 +118,11 @@ class NativeEmitter {
       return "$dynamicName('$name').$nativeName";
     }
 
+    String isolatePrototype = '${compiler.namer.ISOLATE}.prototype';
     for (Element member in classElement.members) {
       if (member.isInstanceMember()) {
         compiler.emitter.addInstanceMember(
-            member, attachTo, buffer, isNative: true);
+            member, attachTo, buffer, isolatePrototype, isNative: true);
       }
     }
 
@@ -302,7 +304,7 @@ class NativeEmitter {
 
   bool isSupertypeOfNativeClass(Element element) {
     if (element.isTypeVariable()) {
-      compiler.cancel("Is check for type variable", element: work.element);
+      compiler.cancel("Is check for type variable", element: element);
       return false;
     }
     if (element.computeType(compiler) is FunctionType) return false;
@@ -322,12 +324,12 @@ class NativeEmitter {
     return isSupertypeOfNativeClass(element);
   }
 
-  void emitIsChecks(StringBuffer buffer) {
+  void emitIsChecks(StringBuffer checkBuffer) {
     for (Element type in compiler.universe.isChecks) {
       if (!requiresNativeIsCheck(type)) continue;
       String name = compiler.namer.operatorIs(type);
-      buffer.add("$defPropName(Object.prototype, '$name', ");
-      buffer.add('function() { return false; });\n');
+      checkBuffer.add("$defPropName(Object.prototype, '$name', ");
+      checkBuffer.add('function() { return false; });\n');
     }
   }