Move V4L2 code into a webcam helper class.

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>
+
+#include "base/macros.h"
+
+namespace extensions {
+
+class Webcam {
+ public:
+  enum PanDirection {
+    PAN_LEFT,
+    PAN_RIGHT,
+    PAN_STOP,
+  };
+
+  enum TiltDirection {
+    TILT_UP,
+    TILT_DOWN,
+    TILT_STOP,
+  };
+
+  Webcam();
+  virtual ~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;
+
+  void AddExtensionRef(const std::string& extension_id) {
+    extension_refs_.insert(extension_id);
+  }
+
+  void RemoveExtensionRef(const std::string& extension_id) {
+    extension_refs_.erase(extension_id);
+  }
+
+  bool ShouldDelete() {
+    return extension_refs_.empty();
+  }
+
+ private:
+  std::set<std::string> extension_refs_;
+
+  DISALLOW_COPY_AND_ASSIGN(Webcam);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_WEBCAM_PRIVATE_WEBCAM_H_