Double clicking the resize handle should expand window along that axis.

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 352 matching lines @@
   }
 }
 
 void WorkspaceManager::OnTypeOfWorkspacedNeededChanged(aura::Window* window) {
   DCHECK(IsManagedWindow(window));
   Workspace* current_workspace = FindBy(window);
   DCHECK(current_workspace);
   Workspace* new_workspace = NULL;
   if (Workspace::TypeForWindow(window) == Workspace::TYPE_MAXIMIZED) {
     // Unmaximized -> maximized; create a new workspace.
-    SetRestoreBounds(window, window->bounds());
+    SetRestoreBoundsIfNotSet(window);
     current_workspace->RemoveWindow(window);
     new_workspace = CreateWorkspace(Workspace::TYPE_MAXIMIZED);
     new_workspace->AddWindowAfter(window, NULL);
     SetFullScreenOrMaximizedBounds(window);
   } else {
     // Maximized -> unmaximized; move window to unmaximized workspace.
     wm::SetOpenWindowSplit(window, false);
     new_workspace = GetManagedWorkspace();
     current_workspace->RemoveWindow(window);
     if (!new_workspace)
@@ skipping 22 matching lines @@
   if (type == Workspace::TYPE_MAXIMIZED)
     workspace = new MaximizedWorkspace(this);
   else
     workspace = new ManagedWorkspace(this);
   AddWorkspace(workspace);
   return workspace;
 }
 
 }  // namespace internal
 }  // namespace ash