refactor(AstParser): make AstParser private, no more injectable

follow up for #788

Closes #818

lib/core/module.dart

@@ -47,7 +47,6 @@ class NgCoreModule extends Module {
     type(ScopeStatsEmitter);
     factory(ScopeStatsConfig, (i) => new ScopeStatsConfig());
     value(Object, {}); // RootScope context
-    type(AstParser);
     type(NgZone);
 
     type(Parser, implementedBy: DynamicParser);

lib/core/scope.dart

@@ -511,7 +511,7 @@ class RootScope extends Scope {
   static final STATE_FLUSH_ASSERT = 'assert';
 
   final ExceptionHandler _exceptionHandler;
-  final AstParser _astParser;
+  final _AstParser _astParser;
   final Parser _parser;
   final ScopeDigestTTL _ttl;
   final NgZone _zone;
@@ -529,7 +529,7 @@ class RootScope extends Scope {
             ScopeStats _scopeStats)
       : _scopeStats = _scopeStats,
         _parser = parser,
-        _astParser = new AstParser(parser),
+        _astParser = new _AstParser(parser),
         super(context, null, null,
             new RootWatchGroup(fieldGetterFactory,
                 new DirtyCheckingChangeDetector(fieldGetterFactory), context),
@@ -948,25 +948,24 @@ class _FunctionChain {
   }
 }
 
-@NgInjectableService()
-class AstParser {
+class _AstParser {
   final Parser _parser;
   int _id = 0;
   ExpressionVisitor _visitor = new ExpressionVisitor();
 
-  AstParser(this._parser);
+  _AstParser(this._parser);
 
-  AST call(String exp, { FilterMap filters,
-                         bool collection: false,
-                         Object context: null }) {
+  AST call(String input, {FilterMap filters,
+                          bool collection: false,
+                          Object context: null }) {
     _visitor.filters = filters;
     AST contextRef = _visitor.contextRef;
     try {
       if (context != null) {
         _visitor.contextRef = new ConstantAST(context, '#${_id++}');
       }
-      var ast = _parser(exp);
-      return collection ? _visitor.visitCollection(ast) : _visitor.visit(ast);
+      var exp = _parser(input);
+      return collection ? _visitor.visitCollection(exp) : _visitor.visit(exp);
     } finally {
       _visitor.contextRef = contextRef;
       _visitor.filters = null;

test/angular_spec.dart

@@ -167,7 +167,6 @@ main() {
         "angular.core.UnboundedCache",  // internal?
         "angular.core.ScopeStream",  // internal?
         "angular.core.FilterMap",  // internal?
-        "angular.core.AstParser",  // internal?
         "angular.watch_group.FunctionApply",  // internal?
         "angular.watch_group.WatchGroup",  // internal?
         "angular.watch_group.ContextReferenceAST",  // internal?

test/change_detection/watch_group_spec.dart

@@ -17,18 +17,20 @@ void main() {
     var watchGrp;
     DirtyCheckingChangeDetector changeDetector;
     Logger logger;
-    AstParser parser;
+    Parser parser;
+    ExpressionVisitor visitor;
 
-    beforeEach(inject((Logger _logger, AstParser _parser) {
+    beforeEach(inject((Logger _logger, Parser _parser) {
       context = {};
       var getterFactory = new DynamicFieldGetterFactory();
       changeDetector = new DirtyCheckingChangeDetector(getterFactory);
       watchGrp = new RootWatchGroup(getterFactory, changeDetector, context);
+      visitor = new ExpressionVisitor();
       logger = _logger;
       parser = _parser;
     }));
 
-    AST parse(String expression) => parser(expression);
+    AST parse(String expression) => visitor.visit(parser(expression));
 
     eval(String expression, [evalContext]) {
       AST ast = parse(expression);