Remove Widget::OnRootViewLayout().

ui/views/mus/native_widget_mus.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This has to be before any other includes, else default is picked up.
 // See base/logging for details on this.
 #define NOTIMPLEMENTED_POLICY 5
 
 #include "ui/views/mus/native_widget_mus.h"
 
@@ skipping 1305 matching lines @@
 
 void NativeWidgetMus::SetVisibilityAnimationTransition(
     Widget::VisibilityTransition transition) {
   NOTIMPLEMENTED();
 }
 
 ui::NativeTheme* NativeWidgetMus::GetNativeTheme() const {
   return ui::NativeThemeAura::instance();
 }
 
-void NativeWidgetMus::OnRootViewLayout() {
-  NOTIMPLEMENTED();
-}
-
 bool NativeWidgetMus::IsTranslucentWindowOpacitySupported() const {
   NOTIMPLEMENTED();
   return true;
 }
 
 void NativeWidgetMus::OnSizeConstraintsChanged() {
   if (!window_ || is_parallel_widget_in_window_manager())
     return;
 
   window_->SetSharedProperty<int32_t>(
@@ skipping 234 matching lines @@
 
   gfx::Path mask_path;
   native_widget_delegate_->GetHitTestMask(&mask_path);
   // TODO(jamescook): Use the full path for the mask.
   gfx::Rect mask_rect =
       gfx::ToEnclosingRect(gfx::SkRectToRectF(mask_path.getBounds()));
   window_->SetHitTestMask(mask_rect);
 }
 
 }  // namespace views