Battery Status API: add plumbing for multi-platform support.

content/browser/battery_status/battery_status_manager.h

+// Copyright 2014 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 CHROME_BROWSER_BATTERY_STATUS_BATTERY_STATUS_MANAGER_H_
+#define CHROME_BROWSER_BATTERY_STATUS_BATTERY_STATUS_MANAGER_H_
+
+#include "build/build_config.h"
+
+#if defined(OS_ANDROID)
+#include "base/android/scoped_java_ref.h"
+#endif
+
+#include "content/browser/battery_status/battery_status_update_callback.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Platform specific manager class for fetching battery status data.
+class CONTENT_EXPORT BatteryStatusManager {
+ public:
+  explicit BatteryStatusManager(const BatteryStatusUpdateCallback& callback);
+  virtual ~BatteryStatusManager();
+
+  // Start listening for battery status changes. New updates are signalled
+  // by invoking the callback provided at construction time.
+  bool StartListeningBatteryChange();
+
+  // Stop listenting for battery status changes.
+  void StopListeningBatteryChange();
+
+#if defined(OS_ANDROID)
+  // Must be called at startup.
+  static bool Register(JNIEnv* env);
+
+  // Called from Java via JNI.
+  void GotBatteryStatus(JNIEnv*, jobject, jboolean charging,
+                        jdouble charging_time, jdouble discharging_time,
+                        jdouble level);
+#endif
+
+ private:
+#if defined(OS_ANDROID)
+  // Java provider of battery status info.
+  base::android::ScopedJavaGlobalRef<jobject> j_manager_;
+#endif
+  BatteryStatusUpdateCallback callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(BatteryStatusManager);
+};
+
+}  // namespace content
+
+#endif  // CHROME_BROWSER_BATTERY_STATUS_BATTERY_STATUS_MANAGER_H_