Adds the option of aligning the launcher to the left or right. There

ash/launcher/launcher_button_host.h

Index: ash/launcher/launcher_button_host.h
diff --git a/ash/launcher/launcher_button_host.h b/ash/launcher/launcher_button_host.h
index 4fbef0347744dbd033f74acbac610653e74bc9f4..ef8a3be3a3dc0ff899cc76abd670b0a04d0d30df 100644
--- a/ash/launcher/launcher_button_host.h
+++ b/ash/launcher/launcher_button_host.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "ash/ash_export.h"
+#include "ash/wm/shelf_auto_hide_behavior.h"
 #include "base/string16.h"
 
 namespace views {
@@ -36,6 +37,8 @@ class ASH_EXPORT LauncherButtonHost {
   // Invoked when the mouse exits the item.
   virtual void MouseExitedButton(views::View* view) = 0;
 
+  virtual ShelfAlignment GetShelfAlignment() const = 0;
+
   // Invoked to get the accessible name of the item.
   virtual string16 GetAccessibleName(const views::View* view) = 0;