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

ash/wm/workspace/workspace_manager.cc

 // 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.
 
 #include "ash/wm/workspace/workspace_manager.h"
 
 #include <algorithm>
 
 #include "ash/shell.h"
 #include "ash/wm/property_util.h"
@@ skipping 70 matching lines @@
     Workspace* workspace = workspaces_[i];
     for (size_t j = 0; j < workspace->windows().size(); ++j)
       workspace->windows()[j]->RemoveObserver(this);
   }
   std::vector<Workspace*> copy_to_delete(workspaces_);
   STLDeleteElements(&copy_to_delete);
 }
 
 bool WorkspaceManager::IsManagedWindow(aura::Window* window) const {
   return window->type() == aura::client::WINDOW_TYPE_NORMAL &&
-         !window->transient_parent();
+         !window->transient_parent() && ash::GetTrackedByWorkspace(window);
 }
 
 void WorkspaceManager::AddWindow(aura::Window* window) {
   DCHECK(IsManagedWindow(window));
 
   Workspace* current_workspace = FindBy(window);
   if (current_workspace) {
     // Already know about this window. Make sure the workspace is active.
     if (active_workspace_ != current_workspace) {
       if (active_workspace_)
@@ skipping 77 matching lines @@
 
 gfx::Rect WorkspaceManager::AlignBoundsToGrid(const gfx::Rect& bounds) {
   if (grid_size_ <= 1)
     return bounds;
   return AlignRectToGrid(bounds, grid_size_);
 }
 
 void WorkspaceManager::OnWindowPropertyChanged(aura::Window* window,
                                                const void* key,
                                                intptr_t old) {
-  if (!IsManagedWindow(window))
-    return;
-
-  if (key != aura::client::kShowStateKey)
+  if (key != aura::client::kShowStateKey || !IsManagedWindow(window))
     return;
 
   DCHECK(FindBy(window));
 
   Workspace::Type old_type = FindBy(window)->type();
   Workspace::Type new_type = Workspace::TypeForWindow(window);
   if (new_type != old_type) {
     OnTypeOfWorkspacedNeededChanged(window);
   } else if (new_type == Workspace::TYPE_MAXIMIZED) {
     // Even though the type didn't change, the window may have gone from
@@ skipping 198 matching lines @@
   if (type == Workspace::TYPE_MAXIMIZED)
     workspace = new MaximizedWorkspace(this);
   else
     workspace = new ManagedWorkspace(this);
   AddWorkspace(workspace);
   return workspace;
 }
 
 }  // namespace internal
 }  // namespace ash