Add ClassMirror.isAbstract to the API and VM implementation.

runtime/lib/mirrors_impl.dart

Index: runtime/lib/mirrors_impl.dart
diff --git a/runtime/lib/mirrors_impl.dart b/runtime/lib/mirrors_impl.dart
index 5f0983adfc63b69decde36b37119b53f9d0e08c3..81bd6bcde4505a2b5e0d0bce6118c596f2f224cd 100644
--- a/runtime/lib/mirrors_impl.dart
+++ b/runtime/lib/mirrors_impl.dart
@@ -437,6 +437,7 @@ class _LocalClassMirror extends _LocalObjectMirror
   final Type _reflectedType;
   Symbol _simpleName;
   DeclarationMirror _owner;
+  final bool isAbstract;
   final bool _isGeneric;
   final bool _isMixinAlias;
   final bool _isGenericDeclaration;
@@ -446,6 +447,7 @@ class _LocalClassMirror extends _LocalObjectMirror
                     reflectedType,
                     String simpleName,
                     this._owner,
+                    this.isAbstract,
                     this._isGeneric,
                     this._isMixinAlias,
                     this._isGenericDeclaration)
@@ -804,7 +806,7 @@ class _LocalClassMirror extends _LocalObjectMirror
 class _LocalFunctionTypeMirror extends _LocalClassMirror
     implements FunctionTypeMirror {
   _LocalFunctionTypeMirror(reflectee, reflectedType)
-      : super(reflectee, reflectedType, null, null, false, false, false);
+      : super(reflectee, reflectedType, null, null, false, false, false, false);
 
   bool get _isAnonymousMixinApplication => false;