Implement device enumeration for PPB_VideoCapture_Dev.

ppapi/cpp/dev/video_capture_dev.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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 PPAPI_CPP_DEV_VIDEO_CAPTURE_DEV_H_
 #define PPAPI_CPP_DEV_VIDEO_CAPTURE_DEV_H_
 
+#include <vector>
+
 #include "ppapi/c/dev/pp_video_capture_dev.h"
 #include "ppapi/cpp/resource.h"
 
 namespace pp {
 
+class CompletionCallback;
+class DeviceRef_Dev;
 class Instance;
 
 class VideoCapture_Dev : public Resource {
  public:
   explicit VideoCapture_Dev(const Instance& instance);
   VideoCapture_Dev(PP_Resource resource);
   VideoCapture_Dev(const VideoCapture_Dev& other);
 
+  virtual ~VideoCapture_Dev();
+
+  VideoCapture_Dev& operator=(const VideoCapture_Dev& other);
+
   // Returns true if the required interface is available.
   static bool IsAvailable();
 
-  int32_t StartCapture(const PP_VideoCaptureDeviceInfo_Dev& requested_info,
-                       uint32_t buffer_count);
+  // |devices| must stay alive until either this VideoCapture_Dev object goes
+  // away or |callback| is run.
+  int32_t EnumerateDevices(std::vector<DeviceRef_Dev>* devices,
+                           const CompletionCallback& callback);
+  int32_t Open(const DeviceRef_Dev& device_ref,
+               const PP_VideoCaptureDeviceInfo_Dev& requested_info,
+               uint32_t buffer_count,
+               const CompletionCallback& callback);
+  int32_t StartCapture();
   int32_t ReuseBuffer(uint32_t buffer);
   int32_t StopCapture();
+  void Close();
+
+ private:
+  struct EnumerateDevicesState;
+
+  void AbortEnumerateDevices();
+
+  // |user_data| is an EnumerateDevicesState object. It is this method's
+  // responsibility to delete it.
+  static void OnEnumerateDevicesComplete(void* user_data, int32_t result);
+
+  // Not owned by this object.
+  EnumerateDevicesState* enum_state_;
 };
 
 }  // namespace pp
 
 #endif  // PPAPI_CPP_DEV_VIDEO_CAPTURE_DEV_H_