Nuke WebPassOwnPtr<T> and replace it with std::unique_ptr<T>.

content/renderer/media/rtc_certificate_generator.h

 // Copyright (c) 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 CONTENT_RENDERER_MEDIA_RTC_CERTIFICATE_GENERATOR_H_
 #define CONTENT_RENDERER_MEDIA_RTC_CERTIFICATE_GENERATOR_H_
 
 #include "base/macros.h"
 #include "third_party/WebKit/public/platform/WebRTCCertificate.h"
 #include "third_party/WebKit/public/platform/WebRTCCertificateGenerator.h"
 #include "third_party/WebKit/public/platform/WebRTCKeyParams.h"
 
 namespace content {
 
 // Chromium's WebRTCCertificateGenerator implementation; uses the
 // PeerConnectionIdentityStore/SSLIdentity::Generate to generate the identity,
 // rtc::RTCCertificate and content::RTCCertificate.
 class RTCCertificateGenerator : public blink::WebRTCCertificateGenerator {
  public:
   RTCCertificateGenerator() {}
   ~RTCCertificateGenerator() override {}
 
   // blink::WebRTCCertificateGenerator implementation.
   void generateCertificate(
       const blink::WebRTCKeyParams& key_params,
       const blink::WebURL& url,
       const blink::WebURL& first_party_for_cookies,
-      blink::WebPassOwnPtr<blink::WebRTCCertificateCallback> observer) override;
+      std::unique_ptr<blink::WebRTCCertificateCallback> observer) override;
   bool isSupportedKeyParams(const blink::WebRTCKeyParams& key_params) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(RTCCertificateGenerator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_CERTIFICATE_GENERATOR_H_