Fix a crasher with "select file" dialogs.

views/widget/widget_win.cc

Index: views/widget/widget_win.cc
diff --git a/views/widget/widget_win.cc b/views/widget/widget_win.cc
index c88e2186086e4259558a68387554b1569727a633..2b4c649a3f54ac4f65cab0a1f2bb21ab879de663 100644
--- a/views/widget/widget_win.cc
+++ b/views/widget/widget_win.cc
@@ -65,6 +65,11 @@ WidgetWin::~WidgetWin() {
 
 // static
 WidgetWin* WidgetWin::GetWidget(HWND hwnd) {
+  // TODO(jcivelli): http://crbug.com/44499 We need a way to test that hwnd is
+  //                 associated with a WidgetWin (it might be a pure
+  //                 WindowImpl).
+  if (!WindowImpl::IsWindowImpl(hwnd))
+    return NULL;
   return reinterpret_cast<WidgetWin*>(win_util::GetWindowUserData(hwnd));
 }