Sets the background color of shelf is opaque black when maximized (2nd)

ash/shelf/shelf_widget.cc

Index: ash/shelf/shelf_widget.cc
diff --git a/ash/shelf/shelf_widget.cc b/ash/shelf/shelf_widget.cc
index ad11e7d792c6841833853db4be23664b894bf092..1f83de44270ca079ad94f1d2ce72629f84b9455c 100644
--- a/ash/shelf/shelf_widget.cc
+++ b/ash/shelf/shelf_widget.cc
@@ -27,6 +27,7 @@
 #include "ui/base/events/event_constants.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/layer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
 #include "ui/gfx/image/image_skia_operations.h"
@@ -44,6 +45,7 @@ const int kDimAlpha = 128;
 // The time to dim and un-dim.
 const int kTimeToDimMs = 3000;  // Slow in dimming.
 const int kTimeToUnDimMs = 200;  // Fast in activating.
+const int kTimeToSwitchBackgroundMs = 1000;
 
 // Class used to slightly dim shelf items when maximized and visible.
 class DimmerView : public views::View,
@@ -246,6 +248,8 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
     return focus_cycler_;
   }
 
+  ui::Layer* opaque_background() { return &opaque_background_; }
+
   // Set if the shelf area is dimmed (eg when a window is maximized).
   void SetDimmed(bool dimmed);
   bool GetDimmed() const;
@@ -253,6 +257,8 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
   // Set the bounds of the widget.
   void SetWidgetBounds(const gfx::Rect bounds);
 
+  void SetParentLayer(ui::Layer* layer);
+
   // views::View overrides:
   virtual void OnPaintBackground(gfx::Canvas* canvas) OVERRIDE;
 
@@ -266,6 +272,8 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
 
   virtual bool CanActivate() const OVERRIDE;
   virtual void Layout() OVERRIDE;
+  virtual void ReorderChildLayers(ui::Layer* parent_layer) OVERRIDE;
+  virtual void OnBoundsChanged(const gfx::Rect& old_bounds) OVERRIDE;
 
   // BackgroundAnimatorDelegate overrides:
   virtual void UpdateBackground(int alpha) OVERRIDE;
@@ -292,6 +300,7 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
   scoped_ptr<views::Widget> dimmer_;
   internal::FocusCycler* focus_cycler_;
   int alpha_;
+  ui::Layer opaque_background_;
 
   // The view which does the dimming.
   DimmerView* dimmer_view_;
@@ -306,9 +315,13 @@ ShelfWidget::DelegateView::DelegateView(ShelfWidget* shelf)
     : shelf_(shelf),
       focus_cycler_(NULL),
       alpha_(0),
+      opaque_background_(ui::LAYER_SOLID_COLOR),
       dimmer_view_(NULL),
       disable_dimming_animations_for_test_(false) {
   set_allow_deactivate_on_esc(true);
+  opaque_background_.SetColor(SK_ColorBLACK);
+  opaque_background_.SetBounds(GetLocalBounds());
+  opaque_background_.SetOpacity(0.0f);
 }
 
 ShelfWidget::DelegateView::~DelegateView() {
@@ -351,6 +364,11 @@ void ShelfWidget::DelegateView::SetWidgetBounds(const gfx::Rect bounds) {
     dimmer_->SetBounds(bounds);
 }
 
+void ShelfWidget::DelegateView::SetParentLayer(ui::Layer* layer) {
+  layer->Add(&opaque_background_);
+  ReorderLayers();
+}
+
 void ShelfWidget::DelegateView::OnPaintBackground(gfx::Canvas* canvas) {
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   gfx::ImageSkia launcher_background =
@@ -405,6 +423,15 @@ void ShelfWidget::DelegateView::Layout() {
   }
 }
 
+void ShelfWidget::DelegateView::ReorderChildLayers(ui::Layer* parent_layer) {
+  views::View::ReorderChildLayers(parent_layer);
+  parent_layer->StackAtBottom(&opaque_background_);
+}
+
+void ShelfWidget::DelegateView::OnBoundsChanged(const gfx::Rect& old_bounds) {
+  opaque_background_.SetBounds(GetLocalBounds());
+}
+
 void ShelfWidget::DelegateView::ForceUndimming(bool force) {
   if (GetDimmed())
     dimmer_view_->ForceUndimming(force);
@@ -445,6 +472,7 @@ ShelfWidget::ShelfWidget(aura::Window* shelf_container,
   // The shelf should not take focus when initially shown.
   set_focus_on_creation(false);
   SetContentsView(delegate_view_);
+  delegate_view_->SetParentLayer(GetLayer());
 
   status_area_widget_ = new internal::StatusAreaWidget(status_container);
   status_area_widget_->CreateTrayViews();
@@ -471,9 +499,34 @@ ShelfWidget::~ShelfWidget() {
 }
 
 void ShelfWidget::SetPaintsBackground(
-    bool value,
+    ShelfBackgroundType background_type,
     internal::BackgroundAnimator::ChangeType change_type) {
-  background_animator_.SetPaintsBackground(value, change_type);
+  ui::Layer* opaque_background = delegate_view_->opaque_background();
+  float target_opacity =
+      (background_type == SHELF_BACKGROUND_MAXIMIZED) ? 1.0f : 0.0f;
+  scoped_ptr<ui::ScopedLayerAnimationSettings> opaque_background_animation;
+  if (change_type != internal::BackgroundAnimator::CHANGE_IMMEDIATE) {
+    opaque_background_animation.reset(new ui::ScopedLayerAnimationSettings(
+        opaque_background->GetAnimator()));
+    opaque_background_animation->SetTransitionDuration(
+        base::TimeDelta::FromMilliseconds(kTimeToSwitchBackgroundMs));
+  }
+  opaque_background->SetOpacity(target_opacity);
+
+  // TODO(mukai): use ui::Layer on both opaque_background and normal background
+  // retire background_animator_ at all. It would be simpler.
+  background_animator_.SetPaintsBackground(
+      background_type != SHELF_BACKGROUND_DEFAULT,
+      change_type);
+}
+
+ShelfBackgroundType ShelfWidget::GetBackgroundType() const {
+  if (delegate_view_->opaque_background()->GetTargetOpacity() == 1.0f)
+    return SHELF_BACKGROUND_MAXIMIZED;
+  if (background_animator_.paints_background())
+    return SHELF_BACKGROUND_OVERLAP;
+
+  return SHELF_BACKGROUND_DEFAULT;
 }
 
 ShelfAlignment ShelfWidget::GetAlignment() const {