dart2js cps: Refactor CallExpressions into Primitives.

pkg/compiler/lib/src/cps_ir/share_final_fields.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.cps_ir.share_final_fields;
 
 import 'optimizers.dart';
 import 'cps_ir_nodes.dart';
 import 'loop_hierarchy.dart';
 import '../elements/elements.dart';
@@ skipping 87 matching lines @@
       return next;
     }
 
     Primitive refinedReceiver = primitive.object.definition;
     Primitive receiver = refinedReceiver.effectiveDefinition;
 
     // Try to reuse an existing load for the same input.
     var map = fieldValues.putIfAbsent(field, () => <Primitive,Primitive>{});
     Primitive existing = map[receiver];
     if (existing != null) {
-      existing.substituteFor(primitive);
-      primitive.destroy();
+      primitive..replaceUsesWith(existing)..destroy();
       node.remove();
       return next;
     }
 
     map[receiver] = primitive;
 
     if (primitive.objectIsNotNull) {
       // Determine how far the GetField can be lifted. The outermost loop that
       // contains the input binding should also contain the load.
       // Don't move above a refinement guard since that might be unsafe.
@@ skipping 52 matching lines @@
       }
     }
     return c1;
   }
 
   int getDepth(Continuation loop) {
     if (loop == null) return -1;
     return loopHierarchy.loopDepth[loop];
   }
 }