Layout panels on top of their launcher icons

ash/wm/panel_layout_manager.h

Index: ash/wm/panel_layout_manager.h
diff --git a/ash/wm/panel_layout_manager.h b/ash/wm/panel_layout_manager.h
index 6951c296822cdf8882ecb9cc47be3442fd39b1fb..4a2f7fee53ecee897626378f1da58e8a68064e0e 100644
--- a/ash/wm/panel_layout_manager.h
+++ b/ash/wm/panel_layout_manager.h
@@ -9,6 +9,7 @@
 #include <list>
 
 #include "ash/ash_export.h"
+#include "ash/launcher/launcher_icons_observer.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/aura/layout_manager.h"
@@ -22,6 +23,8 @@ class Rect;
 }
 
 namespace ash {
+class Launcher;
+
 namespace internal {
 
 // PanelLayoutManager is responsible for organizing panels within the
@@ -43,6 +46,8 @@ class ASH_EXPORT PanelLayoutManager : public aura::LayoutManager {
 
   void ToggleMinimize(aura::Window* panel);
 
+  void SetLauncher(ash::Launcher* launcher);
+
   // Overridden from aura::LayoutManager:
   virtual void OnWindowResized() OVERRIDE;
   virtual void OnWindowAddedToLayout(aura::Window* child) OVERRIDE;
@@ -53,6 +58,15 @@ class ASH_EXPORT PanelLayoutManager : public aura::LayoutManager {
                               const gfx::Rect& requested_bounds) OVERRIDE;
 
  private:
+  class LauncherIconsObserver : public ash::LauncherIconsObserver {

[sky, 2012/04/03 20:39:37]

Any reason you don't make PanelLayoutManager directly implement this as we do
everywhere else?

[Dmitry Lomov (no reviews), 2012/04/03 20:50:07]

The fact that PanelLayoutManager observes launcher icons is its implementation
detail, it is not a fact of its public interface.

[sky, 2012/04/03 20:57:18]

There are a plethora of classes in Chrome that fit this bill. As I mentioned, we
generally don't add another layer just to hide the interface. 

[Dmitry Lomov (no reviews), 2012/04/03 21:18:23]

Widespread use of errant practice does not make it commendable.

[stevenjb, 2012/04/03 22:09:29]

I have to agree with sky here - we make "correctness" vs. "simplicity" tradeoffs
all the time. In Chrome, Observer and Delegate interfaces are generally
inherited because it makes the code easier to follow.

On 2012/04/03 21:18:23, Dmitry Lomov (chromium) wrote:

+   public:
+    LauncherIconsObserver(PanelLayoutManager* layout_manager);
+
+    virtual void OnLauncherIconPositionsChanged() OVERRIDE;
+   private:
+    PanelLayoutManager* layout_manager_;
+  };
+
   typedef std::list<aura::Window*> PanelList;
 
   // Called whenever the panel layout might change.
@@ -67,6 +81,8 @@ class ASH_EXPORT PanelLayoutManager : public aura::LayoutManager {
 
   aura::Window* dragged_panel_;
 
+  LauncherIconsObserver launcher_icons_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(PanelLayoutManager);
 };