aura: Draw drop shadows under browsers and menus.

ui/aura/window.cc

Index: ui/aura/window.cc
diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index d1caa0416e6eab3ea3e35464644793eef6d29341..c10ef6a20fd883e509b63178e5123a68df6f6483 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -13,6 +13,7 @@
 #include "ui/aura/event.h"
 #include "ui/aura/event_filter.h"
 #include "ui/aura/layout_manager.h"
+#include "ui/aura/shadow.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/aura/window_observer.h"
 #include "ui/aura/window_types.h"
@@ -30,7 +31,8 @@ Window::Window(WindowDelegate* delegate)
       transient_parent_(NULL),
       id_(-1),
       user_data_(NULL),
-      stops_event_propagation_(false) {
+      stops_event_propagation_(false),
+      show_shadow_(false) {
 }
 
 Window::~Window() {
@@ -74,6 +76,9 @@ void Window::Init(ui::Layer::LayerType layer_type) {
   layer_.reset(new ui::Layer(Desktop::GetInstance()->compositor(), layer_type));
   layer_->SetVisible(false);
   layer_->set_delegate(this);
+
+  if (show_shadow_)
+    InitShadow();
 }
 
 void Window::SetType(WindowType type) {
@@ -190,6 +195,8 @@ void Window::MoveChildAbove(Window* child, Window* other) {
 
   // Reorder the layer.
   layer()->MoveAbove(child->layer(), other->layer());
+  if (child->shadow_.get())
+    layer()->MoveAbove(child->shadow_->layer(), other->layer());
 
   // Move any transient children that share the same parent to be in front of
   // 'child'.
@@ -214,7 +221,11 @@ void Window::AddChild(Window* child) {
   if (child->parent())
     child->parent()->RemoveChild(child);
   child->parent_ = this;
+
+  if (child->shadow_.get())
+    layer_->Add(child->shadow_->layer());
   layer_->Add(child->layer_.get());
+
   children_.push_back(child);
   if (layout_manager_.get())
     layout_manager_->OnWindowAddedToLayout(child);
@@ -250,6 +261,8 @@ void Window::RemoveChild(Window* child) {
   if (desktop)
     desktop->WindowDetachedFromDesktop(child);
   layer_->Remove(child->layer_.get());
+  if (child->shadow_.get())
+    layer_->Remove(child->shadow_->layer());
   children_.erase(i);
 }
 
@@ -405,6 +418,14 @@ int Window::GetIntProperty(const char* name) const {
       GetProperty(name)));
 }
 
+void Window::SetShadowVisible(bool visible) {
+  show_shadow_ = visible;
+  if (visible && !shadow_.get() && layer())
+    InitShadow();
+  else if (shadow_.get())
+    shadow_->layer()->SetVisible(visible);
+}
+
 Desktop* Window::GetDesktop() {
   return parent_ ? parent_->GetDesktop() : NULL;
 }
@@ -418,6 +439,8 @@ void Window::SetBoundsInternal(const gfx::Rect& new_bounds) {
   // Always need to set the layer's bounds -- even if it is to the same thing.
   // This may cause important side effects such as stopping animation.
   layer_->SetBounds(new_bounds);
+  if (shadow_.get())
+    shadow_->SetContentBounds(new_bounds);
 
   // If we're not changing the effective bounds, then we can bail early and skip
   // notifying our listeners.
@@ -442,6 +465,10 @@ void Window::SetVisible(bool visible) {
     if (delegate_)
       delegate_->OnWindowVisibilityChanged(is_visible);
   }
+
+  if (shadow_.get())
+    shadow_->layer()->SetVisible(show_shadow_ && visible);
+
   if (parent_ && parent_->layout_manager_.get())
     parent_->layout_manager_->OnChildWindowVisibilityChanged(this, visible);
   FOR_EACH_OBSERVER(WindowObserver, observers_,
@@ -490,6 +517,25 @@ Window* Window::GetWindowForPoint(const gfx::Point& local_point,
   return delegate_ ? this : NULL;
 }
 
+void Window::InitShadow() {
+  DCHECK(layer());
+
+  shadow_.reset(new internal::Shadow());
+  shadow_->Init();
+  if (parent_) {
+    // Stack the shadow directly below |layer_|.
+    parent_->layer_->Add(shadow_->layer());
+    // TODO(derat): Add a MoveBelow() method and use that instead (although we
+    // then run the risk of things getting stacked between a window and its
+    // shadow).
+    parent_->layer_->MoveAbove(shadow_->layer(), layer_.get());
+    parent_->layer_->MoveAbove(layer_.get(), shadow_->layer());
+  }
+
+  shadow_->SetContentBounds(bounds());
+  shadow_->layer()->SetVisible(show_shadow_);
+}
+
 void Window::OnPaintLayer(gfx::Canvas* canvas) {
   if (delegate_)
     delegate_->OnPaint(canvas);