Add mixin support to source mirrors.

sdk/lib/_internal/compiler/implementation/mirrors/mirrors.dart

Index: sdk/lib/_internal/compiler/implementation/mirrors/mirrors.dart
diff --git a/sdk/lib/_internal/compiler/implementation/mirrors/mirrors.dart b/sdk/lib/_internal/compiler/implementation/mirrors/mirrors.dart
index 7347573e22e7a69d4cd036641f13204968a57ab5..8e836430ae6e2a4b13c969a6bddacbf5bdbe3741 100644
--- a/sdk/lib/_internal/compiler/implementation/mirrors/mirrors.dart
+++ b/sdk/lib/_internal/compiler/implementation/mirrors/mirrors.dart
@@ -64,6 +64,10 @@ abstract class DeclarationMirror implements Mirror {
    */
   String get simpleName;
 
+  /// Returns `true` if the name of this declaration is generated by the
+  /// provider of the mirror system.
+  bool get isNameSynthetic;
+
   /**
    * Returns the name of this entity qualified by is enclosing context. For
    * instance, the qualified name of a method 'method' in class 'Class' in
@@ -107,7 +111,7 @@ abstract class DeclarationMirror implements Mirror {
   /**
    * Looks up [name] in the scope of this declaration.
    *
-   * [name] may be either a single identifier, like 'foo', or of the 
+   * [name] may be either a single identifier, like 'foo', or of the
    * a prefixed identifier, like 'foo.bar', where 'foo' must be a prefix.
    * For methods and constructors, the scope includes the parameters. For
    * classes and typedefs, the scope includes the type variables.
@@ -368,6 +372,13 @@ abstract class ClassMirror implements TypeMirror, ContainerMirror {
   List<ClassMirror> get superinterfaces;
 
   /**
+   * The mixin of this class. If this class is the result of a mixin application
+   * of the form S with M, returns a class mirror on M. Otherwise return the
+   * class mirror itself.
+   */
+  ClassMirror get mixin;
+
+  /**
    * Is [:true:] iff this type is a class.
    */
   bool get isClass;