Add window states docked; and docked minimized. Add wm window event to set docked and undocked.

ash/wm/dock/docked_window_layout_manager.h

Index: ash/wm/dock/docked_window_layout_manager.h
diff --git a/ash/wm/dock/docked_window_layout_manager.h b/ash/wm/dock/docked_window_layout_manager.h
index 51b302ec3cf0bfeab47e1605d50dc4e2a953afd5..174eeae6aa81ec5f37c8cb87401662a6ab52738c 100644
--- a/ash/wm/dock/docked_window_layout_manager.h
+++ b/ash/wm/dock/docked_window_layout_manager.h
@@ -107,6 +107,11 @@ class ASH_EXPORT DockedWindowLayoutManager
   // Records |action| by |source| in UMA.
   void FinishDragging(DockedAction action, DockedActionSource source);
 
+  // Checks the rules and possibly updates the docked layout to match
+  // the |alignment|. May not apply the |alignment| when
+  // the current shelf alignment conflicts. Never clears the |alignment_|.
+  void MaybeSetDesiredDockedAlignment(DockedAlignment alignment);
+
   Shelf* shelf() { return shelf_; }
   void SetShelf(Shelf* shelf);
 
@@ -183,6 +188,13 @@ class ASH_EXPORT DockedWindowLayoutManager
   // Ideal (starting) width of the dock.
   static const int kIdealWidth;
 
+  // Returns the alignment of the docked windows other than the |child|.
+  DockedAlignment CalculateAlignmentExcept(const aura::Window* child) const;
+
+  // Determines if the |alignment| is applicable taking into account
+  // the shelf alignment.
+  bool IsDockedAlignmentValid(DockedAlignment alignment) const;
+
   // Keep at most kMaxVisibleWindows visible in the dock and minimize the rest
   // (except for |child|).
   void MaybeMinimizeChildrenExcept(aura::Window* child);