Layout panels on top of their launcher icons

ash/wm/panel_layout_manager.cc

Index: ash/wm/panel_layout_manager.cc
diff --git a/ash/wm/panel_layout_manager.cc b/ash/wm/panel_layout_manager.cc
index d793428d12e41b278e119e66eaea1f9dc6ce21d2..227168847f4633178b0ccdc8ec69d37efdda8588 100644
--- a/ash/wm/panel_layout_manager.cc
+++ b/ash/wm/panel_layout_manager.cc
@@ -41,6 +41,9 @@ PanelLayoutManager::PanelLayoutManager(aura::Window* panel_container)
 }
 
 PanelLayoutManager::~PanelLayoutManager() {
+  ash::Launcher* launcher = ash::Shell::GetInstance()->launcher();
+  if (launcher != NULL)
+    launcher->RemoveIconObserver(this);
 }
 
 void PanelLayoutManager::StartDragging(aura::Window* panel) {
@@ -55,6 +58,10 @@ void PanelLayoutManager::FinishDragging() {
   Relayout();
 }
 
+void PanelLayoutManager::SetLauncher(ash::Launcher* launcher) {
+  launcher->AddIconObserver(this);
+}
+
 void PanelLayoutManager::ToggleMinimize(aura::Window* panel) {
   DCHECK(panel->parent() == panel_container_);
   if (panel->GetProperty(aura::client::kShowStateKey) ==
@@ -148,44 +155,48 @@ void PanelLayoutManager::SetChildBounds(aura::Window* child,
 ////////////////////////////////////////////////////////////////////////////////
 // PanelLayoutManager private implementation:
 
+
+void PanelLayoutManager::OnLauncherIconPositionsChanged() {
+  Relayout();
+}
+
 // This is a rough outline of a simple panel layout manager.
 void PanelLayoutManager::Relayout() {
   if (in_layout_)
     return;
   AutoReset<bool> auto_reset_in_layout(&in_layout_, true);
 
-  // Panels are currently laid out just above the launcher (if it exists),
-  // otherwise at the bottom of the root window.
-  int right, bottom;
   ash::Shell* shell = ash::Shell::GetInstance();
-  if (shell->launcher() && shell->launcher()->widget()->IsVisible()) {
-    const gfx::Rect& bounds =
-        shell->launcher()->widget()->GetWindowScreenBounds();
-    right = bounds.width() - 1 - kPanelMarginEdge;
-    bottom = bounds.y() - 1;
-  } else {
-    const gfx::Rect& bounds = panel_container_->GetRootWindow()->bounds();
-    right = bounds.width() - 1 - kPanelMarginEdge;
-    bottom = bounds.bottom() - 1;
-  }
 
-  // Layout the panel windows right to left.
   for (PanelList::iterator iter = panel_windows_.begin();
        iter != panel_windows_.end(); ++iter) {
     aura::Window* panel_win = *iter;
     if (!panel_win->IsVisible())
       continue;
-    int x = right - panel_win->bounds().width();
-    int y = bottom - panel_win->bounds().height();
+
+    gfx::Rect icon_rect =
+        shell->launcher()->GetScreenBoundsOfItemIconForWindow(panel_win);
+
+    // Empty rect indicates that there is no icon for the panel in the launcher,
+    // so there is nowhere to attach it to. Keeping the bounds.
+    if (icon_rect.IsEmpty())
+      continue;
 
     // Do not relayout dragged panel, but pretend it is in place
     if (panel_win != dragged_panel_) {
-      gfx::Rect bounds(x, y,
-                       panel_win->bounds().width(),
-                       panel_win->bounds().height());
+      gfx::Point icon_origin = icon_rect.origin();
+      aura::Window::ConvertPointToWindow(panel_container_->GetRootWindow(),
+                                         panel_container_, &icon_origin);
+
+      gfx::Rect current_bounds = panel_win->bounds();
+
+      gfx::Rect bounds(
+          icon_origin.x() + icon_rect.width()/2 - current_bounds.width()/2,
+          icon_origin.y() - current_bounds.height(),
+          current_bounds.width(),
+          current_bounds.height());
       SetChildBoundsDirect(panel_win, bounds);
     }
-    right = x - kPanelMarginMiddle;
   }
 }