Fix a crash on closing cookies and site info bubble.

chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc

Index: chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
diff --git a/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc b/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
index 182aab729467e1b9ac1f168a0cb53f141ff1f593..ef8abe12407b9c79eb6affd7d9980968ef6ddefa 100644
--- a/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
+++ b/chrome/browser/ui/aura/chrome_browser_main_extra_parts_aura.cc
@@ -44,6 +44,9 @@ namespace {
 
 #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
 ui::NativeTheme* GetNativeThemeForWindow(aura::Window* window) {
+  if (!window)
+    return NULL;
+
   Profile* profile = NULL;
   if (window->type() == ui::wm::WINDOW_TYPE_NORMAL ||
       window->type() == ui::wm::WINDOW_TYPE_POPUP) {