OK, here's john's patch plus my sync stuff.

chrome/browser/ui/panels/panel_extension_browsertest.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 "base/command_line.h"
 #include "base/path_service.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/extensions/extension_browsertest.h"
 #include "chrome/browser/extensions/extension_test_message_listener.h"
@@ skipping 83 matching lines @@
   scoped_ptr<NativePanelTesting> native_panel_testing(
       CreateNativePanelTesting(panel));
   EXPECT_TRUE(native_panel_testing->VerifyAppIcon());
 #endif
 
   panel->Close();
 }
 
 // Tests that icon loading might not be completed when the panel is closed.
 // (crbug.com/151484)
+//
+// TODO(linux_aura) http://crbug.com/163931
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS) && defined(USE_AURA)
+#define MAYBE_ClosePanelBeforeIconLoadingCompleted DISABLED_ClosePanelBeforeIconLoadingCompleted
+#else
+#define MAYBE_ClosePanelBeforeIconLoadingCompleted ClosePanelBeforeIconLoadingCompleted
+#endif
 IN_PROC_BROWSER_TEST_F(PanelExtensionBrowserTest,
-                       ClosePanelBeforeIconLoadingCompleted) {
+                       MAYBE_ClosePanelBeforeIconLoadingCompleted) {
   const Extension* extension =
       LoadExtension(test_data_dir_.AppendASCII("test_extension"));
   Panel* panel = CreatePanelFromExtension(extension);
 
   // Close tha panel without waiting for the app icon loaded.
   panel->Close();
 }
 
 // Non-abstract RenderViewContextMenu class for testing context menus in Panels.
 class PanelContextMenu : public RenderViewContextMenu {
@@ skipping 111 matching lines @@
   EXPECT_FALSE(menu->HasCommandWithId(IDC_SAVE_PAGE));
 
   // Execute the extension's custom menu item and wait for the extension's
   // script to tell us its onclick fired.
   ExtensionTestMessageListener onclick_listener("clicked", false);
   int command_id = IDC_EXTENSIONS_CONTEXT_CUSTOM_FIRST;
   ASSERT_TRUE(menu->IsCommandIdEnabled(command_id));
   menu->ExecuteCommand(command_id);
   EXPECT_TRUE(onclick_listener.WaitUntilSatisfied());
 }