Rename GetRootWindow() -> GetPrimaryRootWindow()

ash/wm/screen_dimmer.cc

 // Copyright (c) 2012 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.
 
 #include "ash/wm/screen_dimmer.h"
 
 #include "ash/shell.h"
 #include "base/time.h"
 #include "ui/aura/root_window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/size.h"
 
 namespace ash {
 namespace internal {
 
 namespace {
 
 // Opacity for |dimming_layer_| when it's dimming the screen.
 const float kDimmingLayerOpacity = 0.4f;
 
 // Duration for dimming animations, in milliseconds.
 const int kDimmingTransitionMs = 200;
 
 }  // namespace
 
 ScreenDimmer::ScreenDimmer() : currently_dimming_(false) {
-  Shell::GetInstance()->GetRootWindow()->AddRootWindowObserver(this);
+  Shell::GetPrimaryRootWindow()->AddRootWindowObserver(this);
 }
 
 ScreenDimmer::~ScreenDimmer() {
-  Shell::GetInstance()->GetRootWindow()->RemoveRootWindowObserver(this);
+  Shell::GetPrimaryRootWindow()->RemoveRootWindowObserver(this);
 }
 
 void ScreenDimmer::SetDimming(bool should_dim) {
   if (should_dim == currently_dimming_)
     return;
 
   if (!dimming_layer_.get()) {
     dimming_layer_.reset(new ui::Layer(ui::LAYER_SOLID_COLOR));
     dimming_layer_->SetColor(SK_ColorBLACK);
     dimming_layer_->SetOpacity(0.0f);
-    ui::Layer* root_layer = Shell::GetRootWindow()->layer();
+    ui::Layer* root_layer = Shell::GetPrimaryRootWindow()->layer();
     dimming_layer_->SetBounds(root_layer->bounds());
     root_layer->Add(dimming_layer_.get());
     root_layer->StackAtTop(dimming_layer_.get());
   }
 
   currently_dimming_ = should_dim;
 
   ui::ScopedLayerAnimationSettings scoped_settings(
       dimming_layer_->GetAnimator());
   scoped_settings.SetTransitionDuration(
       base::TimeDelta::FromMilliseconds(kDimmingTransitionMs));
   dimming_layer_->SetOpacity(should_dim ? kDimmingLayerOpacity : 0.0f);
 }
 
 void ScreenDimmer::OnRootWindowResized(const aura::RootWindow* root,
                                        const gfx::Size& old_size) {
   if (dimming_layer_.get())
     dimming_layer_->SetBounds(gfx::Rect(root->bounds().size()));
 }
 
 }  // namespace internal
 }  // namespace ash