Generalize and refactor DeviceSensorEvent* architecture to support multi-event type targets.

Source/core/frame/DeviceEventControllerBase.h

+/*
+ * Copyright (C) 2014 Google Inc. All rights reserved.

[Inactive, 2014/06/03 13:25:32]

Please use new copyright headers:
http://dev.chromium.org/blink/coding-style#TOC-License

[timvolodine, 2014/06/03 18:45:54]

Done.

+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef DeviceEventControllerBase_h
+#define DeviceEventControllerBase_h
+
+#include "core/page/PageLifecycleObserver.h"
+#include "platform/Timer.h"
+
+namespace WebCore {
+
+// Base controller class for registering controllers with a dispatcher.
+// It watches page visibility and calls stopUpdating when page is not visible.
+// It provides a didUpdateData() callback method which is called when new data
+// it available.
+class DeviceEventControllerBase : public PageLifecycleObserver {
+

[Inactive, 2014/06/03 13:49:33]

nit: Extra line

[timvolodine, 2014/06/03 18:45:54]

Done.

+public:
+    void startUpdating();
+    void stopUpdating();
+
+    // This is called when new data becomes available.
+    virtual void didUpdateData() = 0;
+
+protected:
+    explicit DeviceEventControllerBase(Page*);
+    virtual ~DeviceEventControllerBase();
+
+    virtual void registerWithDispatcher() = 0;
+    virtual void unregisterWithDispatcher() = 0;
+
+    // When true initiates a one-shot didUpdateData() when startUpdating() is called.
+    virtual bool isInvokeInitialUpdate() = 0;
+
+    bool m_hasEventListener;
+
+private:
+    // Inherited from PageLifecycleObserver.
+    virtual void pageVisibilityChanged() OVERRIDE FINAL;
+
+    void oneShotCallback(Timer<DeviceEventControllerBase>*);
+
+    bool m_isActive;
+    Timer<DeviceEventControllerBase> m_timer;
+};
+
+} // namespace WebCore
+
+#endif // DeviceEventControllerBase_h