Initialize members properly

Author: swift-kim

shell/platform/tizen/tizen_event_loop.h

@@ -94,7 +94,7 @@ class TizenRenderEventLoop : public TizenEventLoop {
   virtual void OnTaskExpired() override;
 
  private:
-  TizenRenderer* tizen_renderer_;
+  TizenRenderer* tizen_renderer_{nullptr};
   std::atomic_bool has_pending_renderer_callback_{false};
 };
 #endif

shell/platform/tizen/tizen_renderer_evas_gl.h

@@ -52,11 +52,11 @@ class TizenRendererEvasGL : public TizenRenderer {
   Evas_Object* evas_window_{nullptr};
   Evas_Object* graphics_adapter_{nullptr};
 
-  Evas_GL_Config* gl_config_;
+  Evas_GL_Config* gl_config_{nullptr};
   Evas_GL* evas_gl_{nullptr};
 
-  Evas_GL_Context* gl_context_;
-  Evas_GL_Context* gl_resource_context_;
+  Evas_GL_Context* gl_context_{nullptr};
+  Evas_GL_Context* gl_resource_context_{nullptr};
 
   Evas_GL_Surface* gl_surface_{nullptr};
   Evas_GL_Surface* gl_resource_surface_{nullptr};