Consolidate the code that replaces a TypeParameter with its bound.

pkg/analyzer/lib/src/dart/element/type.dart

Index: pkg/analyzer/lib/src/dart/element/type.dart
diff --git a/pkg/analyzer/lib/src/dart/element/type.dart b/pkg/analyzer/lib/src/dart/element/type.dart
index 1b9c290665b16c8ee63d14e80b244efee4f6cf64..181716c66a83bd36ddac5dfa3521597ef27853d6 100644
--- a/pkg/analyzer/lib/src/dart/element/type.dart
+++ b/pkg/analyzer/lib/src/dart/element/type.dart
@@ -2172,6 +2172,9 @@ abstract class TypeImpl implements DartType {
       [List<FunctionTypeAliasElement> prune]);
 
   @override
+  DartType resolveToBound(DartType objectType) => this;
+
+  @override
   String toString() {
     StringBuffer buffer = new StringBuffer();
     appendTo(buffer);
@@ -2337,6 +2340,15 @@ class TypeParameterTypeImpl extends TypeImpl implements TypeParameterType {
     }
     return types;
   }
+
+  @override
+  DartType resolveToBound(DartType objectType) {
+    if (element.bound == null) {
+      return objectType;
+    }
+
+    return element.bound.resolveToBound(objectType);
+  }
 }
 
 /**