[Extensions Bindings] Lazily initialize NativeHandlers

With native bindings, delay initialization of native handlers until
first access.

Bug: 805244
Change-Id: I4c66ede2ba3f6e05e3b7cfa7ebac0471195646cb
Reviewed-on: https://chromium-review.googlesource.com/892020
Commit-Queue: Devlin <[email protected]>
Reviewed-by: Istiaque Ahmed <[email protected]>
Cr-Commit-Position: refs/heads/master@{#533450}
diff --git a/extensions/renderer/binding_generating_native_handler.h b/extensions/renderer/binding_generating_native_handler.h
index c4e0565e..b49f81d 100644
--- a/extensions/renderer/binding_generating_native_handler.h
+++ b/extensions/renderer/binding_generating_native_handler.h
@@ -26,6 +26,7 @@
                                  const std::string& bind_to);
 
   void Initialize() final;
+  bool IsInitialized() final;
   v8::Local<v8::Object> NewInstance() override;
 
  private: