Check non_client_view_ in Widget::OnSizeConstraintsChanged

This can be nullptr and this is always checked against nullptr
except this place.

BUG=NONE
TEST=covered by unit test

Change-Id: Ie96065820a16dd14552a03d62ae7b06b4e2facb6
Reviewed-on: https://chromium-review.googlesource.com/1105698Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568515}

ui/views/widget/widget.cc

@@ -830,6 +830,7 @@ void Widget::UpdateWindowTitle() {
   base::i18n::AdjustStringForLocaleDirection(&window_title);
   if (!native_widget_->SetWindowTitle(window_title))
     return;
+
   non_client_view_->UpdateWindowTitle();
 
   // If the non-client view is rendering its own title, it'll need to relayout
@@ -995,7 +996,8 @@ bool Widget::IsTranslucentWindowOpacitySupported() const {
 
 void Widget::OnSizeConstraintsChanged() {
   native_widget_->OnSizeConstraintsChanged();
-  non_client_view_->SizeConstraintsChanged();
+  if (non_client_view_)
+    non_client_view_->SizeConstraintsChanged();
 }
 
 void Widget::OnOwnerClosing() {}

ui/views/widget/widget_unittest.cc

@@ -2235,6 +2235,14 @@ TEST_F(WidgetTest, NoCrashOnWidgetDelete) {
   widget->Init(params);
 }
 
+TEST_F(WidgetTest, NoCrashOnResizeConstraintsWindowTitleOnPopup) {
+  std::unique_ptr<Widget> widget(new Widget);
+  Widget::InitParams params = CreateParams(Widget::InitParams::TYPE_POPUP);
+  params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  widget->Init(params);
+  widget->OnSizeConstraintsChanged();
+}
+
 // Tests that we do not crash when a Widget is destroyed before it finishes
 // processing of pending input events in the message loop.
 TEST_F(WidgetTest, NoCrashOnWidgetDeleteWithPendingEvents) {