Compute bounds of type variables.

pkg/front_end/lib/src/fasta/kernel/kernel_type_variable_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_type_variable_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_type_variable_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_type_variable_builder.dart
index cbb2937efd759ed391d8862e0ab6138c44c6aa51..e6c83564fc2d57270f00de9188ea09b5d39f2875 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_type_variable_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_type_variable_builder.dart
@@ -6,7 +6,6 @@ library fasta.kernel_type_variable_builder;
 
 import 'package:kernel/ast.dart' show
     DartType,
-    DynamicType,
     TypeParameter,
     TypeParameterType;
 
@@ -14,6 +13,7 @@ import '../errors.dart' show
     inputError;
 
 import 'kernel_builder.dart' show
+    KernelClassBuilder,
     KernelLibraryBuilder,
     KernelNamedTypeBuilder,
     KernelTypeBuilder,
@@ -25,7 +25,7 @@ class KernelTypeVariableBuilder
 
   KernelTypeVariableBuilder(String name, KernelLibraryBuilder compilationUnit,
       int charOffset, [KernelTypeBuilder bound])
-      : parameter = new TypeParameter(name, const DynamicType()),
+      : parameter = new TypeParameter(name, null),
         super(name, bound, compilationUnit, charOffset);
 
   DartType buildType(List<KernelTypeBuilder> arguments) {
@@ -50,4 +50,8 @@ class KernelTypeVariableBuilder
     return new KernelNamedTypeBuilder(name, null, -1, null)
         ..builder = this;
   }
+
+  void finish(KernelClassBuilder object) {
+    parameter.bound = bound?.build() ?? object.buildType(null);
+  }
 }