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

extensions/browser/api/webcam_private/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_WEBCAM_H_
 #define EXTENSIONS_BROWSER_API_WEBCAM_PRIVATE_WEBCAM_H_
 
 #include <set>
 #include <string>
 
@@ skipping 13 matching lines @@
   };
 
   enum TiltDirection {
     TILT_UP,
     TILT_DOWN,
     TILT_STOP,
   };
 
   Webcam();
 
-  virtual void Reset(bool pan, bool tilt, bool zoom) = 0;
-  virtual bool GetPan(int* value) = 0;
-  virtual bool GetTilt(int* value) = 0;
-  virtual bool GetZoom(int* value) = 0;
-  virtual bool SetPan(int value) = 0;
-  virtual bool SetTilt(int value) = 0;
-  virtual bool SetZoom(int value) = 0;
-  virtual bool SetPanDirection(PanDirection direction) = 0;
-  virtual bool SetTiltDirection(TiltDirection direction) = 0;
+  using GetPTZCompleteCallback = base::Callback<void(bool, int)>;
+  using SetPTZCompleteCallback = base::Callback<void(bool)>;
+
+  virtual void GetPan(const GetPTZCompleteCallback& callback) = 0;
+  virtual void GetTilt(const GetPTZCompleteCallback& callback) = 0;
+  virtual void GetZoom(const GetPTZCompleteCallback& callback) = 0;
+  virtual void SetPan(int value, const SetPTZCompleteCallback& callback) = 0;
+  virtual void SetTilt(int value, const SetPTZCompleteCallback& callback) = 0;
+  virtual void SetZoom(int value, const SetPTZCompleteCallback& callback) = 0;
+  virtual void SetPanDirection(PanDirection direction,
+                               const SetPTZCompleteCallback& callback) = 0;
+  virtual void SetTiltDirection(TiltDirection direction,
+                                const SetPTZCompleteCallback& callback) = 0;
+  virtual void Reset(bool pan,
+                     bool tilt,
+                     bool zoom,
+                     const SetPTZCompleteCallback& callback) = 0;
 
  protected:
   friend class base::RefCounted<Webcam>;
   virtual ~Webcam();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Webcam);
 };
 
 class WebcamResource : public ApiResource {
@@ skipping 15 matching lines @@
  private:
   scoped_refptr<Webcam> webcam_;
   std::string webcam_id_;
 
   DISALLOW_COPY_AND_ASSIGN(WebcamResource);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_WEBCAM_PRIVATE_WEBCAM_H_