[Aura] Support always-on-top top level window.

views/widget/native_widget_aura.cc

 // Copyright (c) 2011 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 "views/widget/native_widget_aura.h"
 
 #include "base/bind.h"
 #include "ui/aura/aura_constants.h"
 #include "ui/aura/desktop.h"
 #include "ui/aura/desktop_observer.h"
@@ skipping 126 matching lines @@
   window_->set_minimum_size(delegate_->GetMinimumSize());
   window_->SetBounds(params.bounds);
   if (params.type == Widget::InitParams::TYPE_CONTROL) {
     window_->SetParent(params.GetParent());
   } else {
     // Set up the transient child before the window is added. This way the
     // LayoutManager knows the window has a transient parent.
     gfx::NativeView parent = params.GetParent();
     if (parent)
       parent->AddTransientChild(window_);
+    // SetAlwaysOnTop before SetParent so that always-on-top container is used.
+    if (params.keep_on_top)
+      SetAlwaysOnTop(true);
     window_->SetParent(NULL);
   }
   // TODO(beng): do this some other way.
   delegate_->OnNativeWidgetSizeChanged(params.bounds.size());
   can_activate_ = params.can_activate;
   if (params.type != Widget::InitParams::TYPE_TOOLTIP && !params.child) {
     DCHECK(GetWidget()->GetRootView());
     views::TooltipManagerViews* manager = new views::TooltipManagerViews(
         GetWidget()->GetRootView());
     tooltip_manager_.reset(manager);
@@ skipping 254 matching lines @@
 
 void NativeWidgetAura::Deactivate() {
   window_->Deactivate();
 }
 
 bool NativeWidgetAura::IsActive() const {
   return aura::Desktop::GetInstance()->active_window() == window_;
 }
 
 void NativeWidgetAura::SetAlwaysOnTop(bool on_top) {
-  // http://crbug.com/102582
-  NOTIMPLEMENTED();
+  switch (window_->type()) {
+    case aura::WINDOW_TYPE_NORMAL:
+    case aura::WINDOW_TYPE_POPUP:
+      SetNativeWindowProperty(aura::kAlwaysOnTopKey,
+          reinterpret_cast<void*>(on_top));
+
+      // Having a parent means it's added to some container already.
+      // Doing SetParent again here to make sure window_ is put in the right
+      // container.
+      // TODO(xiyuan): Optimize and only switch containers when necessary.
+      if (window_->parent()) {
+        window_->parent()->RemoveChild(window_);
+        window_->SetParent(NULL);
+      }
+
+      break;
+    case aura::WINDOW_TYPE_MENU:
+    case aura::WINDOW_TYPE_TOOLTIP:
+      // Menu and tooptip has their own container and ignores always-on-top.
+      break;
+    default:
+      NOTREACHED() << "Window " << window_->id()
+                   << " of type " << window_->type()
+                   << " does not support always-on-top.";
+      break;
+  }
 }
 
 void NativeWidgetAura::Maximize() {
   window_->SetIntProperty(aura::kShowStateKey, ui::SHOW_STATE_MAXIMIZED);
 }
 
 void NativeWidgetAura::Minimize() {
   NOTREACHED();
 }
 
@@ skipping 298 matching lines @@
 
 // static
 bool NativeWidgetPrivate::IsMouseButtonDown() {
   // http://crbug.com/102577
   NOTIMPLEMENTED();
   return false;
 }
 
 }  // namespace internal
 }  // namespace views