Remove Ash shelf dimmer.

ash/common/shelf/wm_shelf.cc

Index: ash/common/shelf/wm_shelf.cc
diff --git a/ash/common/shelf/wm_shelf.cc b/ash/common/shelf/wm_shelf.cc
index e439381929be6836869bb732665d2bf36d8c5d57..87392334d4f62b39757a7cd339b14da401701d69 100644
--- a/ash/common/shelf/wm_shelf.cc
+++ b/ash/common/shelf/wm_shelf.cc
@@ -200,14 +200,6 @@ ShelfBackgroundType WmShelf::GetBackgroundType() const {
   return shelf_widget_->GetBackgroundType();
 }
 
-WmDimmerView* WmShelf::CreateDimmerView(bool disable_animations_for_test) {
-  return nullptr;
-}
-
-bool WmShelf::IsDimmed() const {
-  return shelf_widget_->GetDimsShelf();
-}
-
 bool WmShelf::IsVisible() const {
   return shelf_widget_->IsShelfVisible();
 }