Only setup distillability mojo if needed

components/dom_distiller/content/browser/distillability_driver.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DISTILLIBILITY_DRIVER_H_
 #define COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DISTILLIBILITY_DRIVER_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "components/dom_distiller/content/common/distillability_service.mojom.h"
@@ skipping 25 matching lines @@
       content::RenderFrameHost* new_host) override;
 
  private:
   explicit DistillabilityDriver(content::WebContents* web_contents);
   friend class content::WebContentsUserData<DistillabilityDriver>;
   friend class DistillabilityServiceImpl;
 
   void SetupMojoService(content::RenderFrameHost* frame_host);
   void OnDistillability(bool distillable, bool is_last);
 
+  void SetNeedsMojoSetup();
+
   base::Callback<void(bool, bool)> m_delegate_;
 
+  bool mojo_needs_setup_;
+
   base::WeakPtrFactory<DistillabilityDriver> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DistillabilityDriver);
 };
 
 }  // namespace dom_distiller
 
 #endif  // COMPONENTS_DOM_DISTILLER_CONTENT_BROWSER_DISTILLIBILITY_DRIVER_H_