Change webcamPrivate.set/get/reset to async APIs.

extensions/browser/api/webcam_private/v4l2_webcam.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 EXTENSIONS_BROWSER_API_WEBCAM_PRIVATE_V4L2_WEBCAM_H_
 #define EXTENSIONS_BROWSER_API_WEBCAM_PRIVATE_V4L2_WEBCAM_H_
 
 #include "extensions/browser/api/webcam_private/webcam.h"
 
 #include "base/files/scoped_file.h"
 
 namespace extensions {
 
 class V4L2Webcam : public Webcam {
  public:
   V4L2Webcam(const std::string& device_id);
   bool Open();
 
  private:
   ~V4L2Webcam() override;
   bool EnsureLogitechCommandsMapped();
   bool SetWebcamParameter(int fd, uint32_t control_id, int value);
   bool GetWebcamParameter(int fd, uint32_t control_id, int* value);
 
   // Webcam:
-  void Reset(bool pan, bool tilt, bool zoom) override;
-  bool GetPan(int* value) override;
-  bool GetTilt(int* value) override;
-  bool GetZoom(int* value) override;
-  bool SetPan(int value) override;
-  bool SetTilt(int value) override;
-  bool SetZoom(int value) override;
-  bool SetPanDirection(PanDirection direction) override;
-  bool SetTiltDirection(TiltDirection direction) override;
+  void GetPan(const GetPTZCompleteCallback& callback) override;
+  void GetTilt(const GetPTZCompleteCallback& callback) override;
+  void GetZoom(const GetPTZCompleteCallback& callback) override;
+  void SetPan(int value, const SetPTZCompleteCallback& callback) override;
+  void SetTilt(int value, const SetPTZCompleteCallback& callback) override;
+  void SetZoom(int value, const SetPTZCompleteCallback& callback) override;
+  void SetPanDirection(PanDirection direction,
+                       const SetPTZCompleteCallback& callback) override;
+  void SetTiltDirection(TiltDirection direction,
+                        const SetPTZCompleteCallback& callback) override;
+  void Reset(bool pan,
+             bool tilt,
+             bool zoom,
+             const SetPTZCompleteCallback& callback) override;
 
   const std::string device_id_;
   base::ScopedFD fd_;
 
   DISALLOW_COPY_AND_ASSIGN(V4L2Webcam);
 };
 
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_WEBCAM_PRIVATE_V4L2_WEBCAM_H_