Fixes three crashes

athena/home/home_card_impl.cc

Index: athena/home/home_card_impl.cc
diff --git a/athena/home/home_card_impl.cc b/athena/home/home_card_impl.cc
index 04b649a72993f32b6d63ff20a98bd1b3486b247c..042ff6ce971ff71b88eb52496f256b028e4b6671 100644
--- a/athena/home/home_card_impl.cc
+++ b/athena/home/home_card_impl.cc
@@ -486,6 +486,11 @@ HomeCardImpl::~HomeCardImpl() {
   if (activation_client_)
     activation_client_->RemoveObserver(this);
   home_card_widget_->CloseNow();
+
+  // Reset the view delegate first as it access search provider during
+  // shutdown.
+  view_delegate_.reset();
+  search_provider_.reset();
   instance = NULL;
 }