Privatize StrongBinding lifetime management

chrome/browser/chromeos/attestation/platform_verification_impl.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 CHROME_BROWSER_CHROMEOS_ATTESTATION_PLATFORM_VERIFICATION_IMPL_H_
 #define CHROME_BROWSER_CHROMEOS_ATTESTATION_PLATFORM_VERIFICATION_IMPL_H_
 
 #include <string>
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/chromeos/attestation/platform_verification_flow.h"
 #include "content/public/browser/render_frame_host.h"
 #include "media/mojo/interfaces/platform_verification.mojom.h"
-#include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace chromeos {
 namespace attestation {
 
 // Implements media::mojom::PlatformVerification on ChromeOS using
 // PlatformVerificationFlow. Can only be used on the UI thread because
 // PlatformVerificationFlow lives on the UI thread.
 class PlatformVerificationImpl : public media::mojom::PlatformVerification {
  public:
   static void Create(
       content::RenderFrameHost* render_frame_host,
       mojo::InterfaceRequest<media::mojom::PlatformVerification> request);
 
-  PlatformVerificationImpl(
-      content::RenderFrameHost* render_frame_host,
-      mojo::InterfaceRequest<PlatformVerification> request);
+  explicit PlatformVerificationImpl(
+      content::RenderFrameHost* render_frame_host);
   ~PlatformVerificationImpl() override;
 
   // mojo::InterfaceImpl<PlatformVerification> implementation.
   void ChallengePlatform(const mojo::String& service_id,
                          const mojo::String& challenge,
                          const ChallengePlatformCallback& callback) override;
 
  private:
   using Result = PlatformVerificationFlow::Result;
 
   void OnPlatformChallenged(const ChallengePlatformCallback& callback,
                             Result result,
                             const std::string& signed_data,
                             const std::string& signature,
                             const std::string& platform_key_certificate);
 
-  mojo::StrongBinding<media::mojom::PlatformVerification> binding_;
-
   content::RenderFrameHost* const render_frame_host_;
 
   scoped_refptr<PlatformVerificationFlow> platform_verification_flow_;
 
   base::WeakPtrFactory<PlatformVerificationImpl> weak_factory_;
 };
 
 }  // namespace attestation
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_ATTESTATION_PLATFORM_VERIFICATION_IMPL_H_