dart2js: Use an abstract Name class for names in the generated JavaScript ast.

pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart

Index: pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart b/pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart
index 1b1e100af716ec511c691d98b5ce18a86a2281c5..eeff7d55f5d24553711b3a65b839e9d5d0baf115 100644
--- a/pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/old_emitter/container_builder.dart
@@ -12,16 +12,16 @@ class ContainerBuilder extends CodeEmitterHelper {
 
   void addMemberMethod(DartMethod method, ClassBuilder builder) {
     MethodElement member = method.element;
-    String name = method.name;
+    jsAst.Name name = method.name;
     FunctionSignature parameters = member.functionSignature;
     jsAst.Expression code = method.code;
     bool needsStubs = method.parameterStubs.isNotEmpty;
     bool canBeApplied = method.canBeApplied;
     bool canBeReflected = method.canBeReflected;
     bool canTearOff = method.needsTearOff;
-    String tearOffName = method.tearOffName;
+    jsAst.Name tearOffName = method.tearOffName;
     bool isClosure = method is InstanceMethod && method.isClosure;
-    String superAlias = method is InstanceMethod ? method.aliasName : null;
+    jsAst.Name superAlias = method is InstanceMethod ? method.aliasName : null;
     bool hasSuperAlias = superAlias != null;
     jsAst.Expression memberTypeExpression = method.functionType;
 
@@ -77,7 +77,7 @@ class ContainerBuilder extends CodeEmitterHelper {
 
     // Create the optional aliasing entry if this method is called via super.
     if (hasSuperAlias) {
-      expressions.add(new jsAst.LiteralString('"${superAlias}"'));
+      expressions.add(js.quoteName(superAlias));
     }
 
     expressions.add(code);
@@ -93,9 +93,11 @@ class ContainerBuilder extends CodeEmitterHelper {
       return;
     }
 
-    String callSelectorString = 'null';
-    if (method.callName != null) {
-      callSelectorString = '"${method.callName}"';
+    jsAst.Literal callSelectorString;
+    if (method.callName == null) {
+      callSelectorString = new jsAst.LiteralNull();
+    } else {
+      callSelectorString = js.quoteName(method.callName);
     }
 
     // On [requiredParameterCount], the lower bit is set if this method can be
@@ -106,27 +108,27 @@ class ContainerBuilder extends CodeEmitterHelper {
     int optionalParameterCount = parameters.optionalParameterCount << 1;
     if (parameters.optionalParametersAreNamed) optionalParameterCount++;
 
-    // TODO(sra): Don't use LiteralString for non-strings.
-    List tearOffInfo = [new jsAst.LiteralString(callSelectorString)];
+    List tearOffInfo = [callSelectorString];
 
     for (ParameterStubMethod stub in method.parameterStubs) {
-      String invocationName = stub.name;
+      jsAst.Name invocationName = stub.name;
       emitter.interceptorEmitter
           .recordMangledNameOfMemberMethod(member, invocationName);
 
       expressions.add(stub.code);
       if (member.isInstanceMember) {
-        expressions.add(js.string(invocationName));
+        expressions.add(js.quoteName(invocationName));
       }
-      String callName = stub.callName;
-      String callSelectorString = (callName == null) ? 'null' : '"$callName"';
-      tearOffInfo.add(new jsAst.LiteralString(callSelectorString));
+      jsAst.Name callName = stub.callName;
+      jsAst.Literal callSelectorString =
+          (callName == null) ? new jsAst.LiteralNull() : js.quoteName(callName);
+      tearOffInfo.add(callSelectorString);
     }
 
     expressions
         ..addAll(tearOffInfo)
         ..add((tearOffName == null || member.isAccessor)
-              ? js("null") : js.string(tearOffName))
+              ? js("null") : js.quoteName(tearOffName))
         ..add(js.number(requiredParameterCount))
         ..add(js.number(optionalParameterCount))
         ..add(memberTypeExpression == null ? js("null") : memberTypeExpression)