Gentle start with removing explicit interfaces

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 422 matching lines @@
                                        token_pos,
                                        try_index);
 }
 
 
 void FlowGraphCompiler::GenerateNumberTypeCheck(Register kClassIdReg,
                                                 const AbstractType& type,
                                                 Label* is_instance_lbl,
                                                 Label* is_not_instance_lbl) {
   GrowableArray<intptr_t> args;
-  if (type.IsNumberInterface()) {
+  if (type.IsNumber()) {
     args.Add(kDoubleCid);
     args.Add(kMintCid);
     args.Add(kBigintCid);
   } else if (type.IsIntInterface()) {
     args.Add(kMintCid);
     args.Add(kBigintCid);
   } else if (type.IsDoubleInterface()) {
     args.Add(kDoubleCid);
   }
   CheckClassIds(kClassIdReg, args, is_instance_lbl, is_not_instance_lbl);
@@ skipping 313 matching lines @@
       return;
     }
   }
 
   // This move is not blocked.
   EmitMove(index);
 }
 
 
 }  // namespace dart