Fix crash/leak issue in native_view_host_gtk.cc.

views/controls/native/native_view_host.h

Index: views/controls/native/native_view_host.h
diff --git a/views/controls/native/native_view_host.h b/views/controls/native/native_view_host.h
index 9970901cddaf5b2f817dabaa018c3e3e369868bb..d6115b289606205f8609d1162917ce41d335a396 100644
--- a/views/controls/native/native_view_host.h
+++ b/views/controls/native/native_view_host.h
@@ -81,6 +81,10 @@ class NativeViewHost : public View {
   virtual std::string GetClassName() const;
 
  private:
+  // Detach the native view. |destroyed| is true if the native view is
+  // detached because it's being destroyed, or false otherwise.
+  void Detach(bool destroyed);
+
   // The attached native view.
   gfx::NativeView native_view_;