Layout panels on top of their launcher icons

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index 23a13cdce010f8f3f05b1c2a265379da7f578859..3697cd9a46effeed2d801c5e90c437b0877b9654 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -63,6 +63,7 @@ class DragDropController;
 class FocusCycler;
 class InputMethodEventFilter;
 class MonitorController;
+class PanelLayoutManager;
 class PartialScreenshotEventFilter;
 class ResizeShadowController;
 class RootWindowEventFilter;
@@ -302,6 +303,9 @@ class ASH_EXPORT Shell {
   // the status area.
   internal::ShelfLayoutManager* shelf_;
 
+  // Manages layout of panels. Owned by container of panels.
+  internal::PanelLayoutManager* panel_layout_manager_;
+
   ObserverList<ShellObserver> observers_;
 
   // Owned by aura::RootWindow, cached here for type safety.