Issue 5157. Introduce TypeQuality. Try to find member in subclasses.

compiler/java/com/google/dart/compiler/type/AbstractType.java

Index: compiler/java/com/google/dart/compiler/type/AbstractType.java
diff --git a/compiler/java/com/google/dart/compiler/type/AbstractType.java b/compiler/java/com/google/dart/compiler/type/AbstractType.java
index 221a3d6f34ab9595ccc1dbd9397ff2c642a66d77..3a5892a33ae8047b56f3595461b9a8b1ce4da124 100644
--- a/compiler/java/com/google/dart/compiler/type/AbstractType.java
+++ b/compiler/java/com/google/dart/compiler/type/AbstractType.java
@@ -9,7 +9,7 @@ package com.google.dart.compiler.type;
  */
 abstract class AbstractType implements Type {
   @Override
-  public boolean isInferred() {
-    return false;
+  public TypeQuality getQuality() {
+    return TypeQuality.EXACT;
   }
 }