Revert "Add optional message to assert in Dart2js - continued"

pkg/compiler/lib/src/common/backend_api.dart

Index: pkg/compiler/lib/src/common/backend_api.dart
diff --git a/pkg/compiler/lib/src/common/backend_api.dart b/pkg/compiler/lib/src/common/backend_api.dart
index 71c86165d11cd1d5fea54d9666e27735e3153c70..7af87501643d19b461e288e2620d4a2a93e7c91c 100644
--- a/pkg/compiler/lib/src/common/backend_api.dart
+++ b/pkg/compiler/lib/src/common/backend_api.dart
@@ -167,6 +167,9 @@ abstract class Backend {
   void registerTypeVariableBoundsSubtypeCheck(DartType typeArgument,
                                               DartType bound) {}
 
+  /// Returns `true` if [element] represent the assert function.
+  bool isAssertMethod(Element element) => false;
+
   /**
    * Call this to register that an instantiated generic class has a call
    * method.