Fix the Mac build

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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 "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/class_finalizer.h"
@@ skipping 2775 matching lines @@
                                    args_desc));
       if (!function.IsNull()) {
         const Array& args = Array::Handle(Array::New(kNumArgs));
         args.SetAt(0, instance);
         Instance& index = Instance::Handle(isolate);
         for (intptr_t i = 0; i < length; ++i) {
           index = Integer::New(i);
           args.SetAt(1, index);
           Dart_Handle value = Api::NewHandle(isolate,
               DartEntry::InvokeFunction(function, args));
-          if (Dart_IsError(value))
+          if (::Dart_IsError(value))
             return value;
           result[i] = value;
         }
         return Api::Success();
       }
     }
     return Api::NewError("Object does not implement the 'List' interface");
   }
 }
 
@@ skipping 3210 matching lines @@
   ASSERT(stream != NULL);
   TimelineEvent* event = stream->StartEvent();
   if (event != NULL) {
     event->AsyncEnd(label, async_id);
     event->Complete();
   }
   return Api::Success();
 }
 
 }  // namespace dart