Check for null return from GetNativeView().

ui/keyboard/content/keyboard_ui_content.cc

Index: ui/keyboard/content/keyboard_ui_content.cc
diff --git a/ui/keyboard/content/keyboard_ui_content.cc b/ui/keyboard/content/keyboard_ui_content.cc
index 1b75b6afbb4e0019e2e9abb647a15bcb98f2d10f..d08fd23cd9f656e4fd93989fa29981fb4e65cfa7 100644
--- a/ui/keyboard/content/keyboard_ui_content.cc
+++ b/ui/keyboard/content/keyboard_ui_content.cc
@@ -238,6 +238,12 @@ void KeyboardUIContent::InitInsets(const gfx::Rect& new_bounds) {
     // the render process crashed.
     if (view) {
       aura::Window* window = view->GetNativeView();
+      // Added while we determine if RenderWidgetHostViewChildFrame can be
+      // changed to always return a non-null value: https://crbug.com/644726 .
+      // If we cannot guarantee a non-null value, then this may need to stay.
+      if (!window)
+        continue;
+
       if (ShouldWindowOverscroll(window)) {
         gfx::Rect window_bounds = window->GetBoundsInScreen();
         gfx::Rect intersect = gfx::IntersectRects(window_bounds,