Implement fromEnvironment on bool, int, String in dart2js.

sdk/lib/_internal/compiler/implementation/warnings.dart

 // Copyright (c) 2011, 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.
 
 part of dart2js;
 
 const DONT_KNOW_HOW_TO_FIX = "";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 956 matching lines @@
 
   static const MessageKind VOID_NOT_ALLOWED = const MessageKind(
       "Error: Type 'void' can't be used here because it isn't a return type.",
       howToFix: "Try removing 'void' keyword or replace it with 'var', 'final',"
           " or a type.",
       examples: const [
           "void x; main() {}",
           "foo(void x) {} main() { foo(null); }",
       ]);
 
+  static const MessageKind NULL_NOT_ALLOWED = const MessageKind(
+      "Error: `null` can't be used here.");
+
   static const MessageKind BEFORE_TOP_LEVEL = const MessageKind(
       "Error: Part header must come before top-level definitions.");
 
   static const MessageKind LIBRARY_NAME_MISMATCH = const MessageKind(
       "Warning: Expected part of library name '#{libraryName}'.");
 
   static const MessageKind MISSING_PART_OF_TAG = const MessageKind(
       "Error: This file has no part-of tag, but it is being used as a part.");
 
   static const MessageKind DUPLICATED_PART_OF = const MessageKind(
@@ skipping 568 matching lines @@
 
 class CompileTimeConstantError extends Diagnostic {
   CompileTimeConstantError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }
 
 class CompilationError extends Diagnostic {
   CompilationError(MessageKind kind, Map arguments, bool terse)
     : super(kind, arguments, terse);
 }