Attempt 2: Allows tab dragging when maximized on aura. To fix it I made it so

ash/wm/workspace/workspace_manager.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_WM_WORKSPACE_MANAGER_H_
 #define ASH_WM_WORKSPACE_MANAGER_H_
 
 #include <vector>
 
 #include "ash/ash_export.h"
@@ skipping 13 matching lines @@
 class Rect;
 }
 
 namespace ash {
 namespace internal {
 
 class ShelfLayoutManager;
 class WorkspaceManagerTest;
 
 // WorkspaceManager manages multiple workspaces in the desktop.
-class ASH_EXPORT WorkspaceManager : public aura::WindowObserver{
+class ASH_EXPORT WorkspaceManager : public aura::WindowObserver {
  public:
   explicit WorkspaceManager(aura::Window* viewport);
   virtual ~WorkspaceManager();
 
   // Returns true if |window| should be managed by the WorkspaceManager.
   bool IsManagedWindow(aura::Window* window) const;
 
   // Adds/removes a window creating/destroying workspace as necessary.
   void AddWindow(aura::Window* window);
   void RemoveWindow(aura::Window* window);
@@ skipping 126 matching lines @@
   // Owned by the Shell container window LauncherContainer. May be NULL.
   ShelfLayoutManager* shelf_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceManager);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_MANAGER_H_