Add "force inline" to internal annotations.

sdk/lib/_internal/compiler/js_lib/annotations.dart

 // 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.
 
 part of _js_helper;
 
 /// Tells the optimizing compiler that the annotated method has no
 /// side-effects.
 /// Requires @NoInline() to function correctly.
 class NoSideEffects {
   const NoSideEffects();
 }
 
 /// Tells the optimizing compiler that the annotated method cannot throw.
 /// Requires @NoInline() to function correctly.
 class NoThrows {
   const NoThrows();
 }
 
 /// Tells the optimizing compiler to not inline the annotated method.
 class NoInline {
   const NoInline();
 }
 
+/// Tells the optimizing compiler to always inline the annotated method.
+class ForceInline {
+  const ForceInline();
+}
+
 // Ensures that the annotated method is represented internally using
 // IR nodes ([:value == true:]) or AST nodes ([:value == false:]).
 class IrRepresentation {
   final bool value;
   const IrRepresentation(this.value);
 }
 
 /// Marks a class as native and defines its JavaScript name(s).
 class Native {
   final String name;
   const Native(this.name);
 }
 
 class _Patch {
   final String version;
 
   const _Patch(this.version);
 }
 
 /// Annotation that marks the declaration as a patch.
 const _Patch patch = const _Patch(null);
 
 /// Annotation that marks the declaration as a patch for the old emitter.
 const _Patch patch_old = const _Patch('old');
 
 /// Annotation that marks the declaration as a patch for the new emitter.
 const _Patch patch_new = const _Patch('new');