Add Dispatcher class to the Battery Status API module.

Source/modules/battery/BatteryDispatcher.cpp

Index: Source/modules/battery/BatteryDispatcher.cpp
diff --git a/Source/modules/battery/BatteryDispatcher.cpp b/Source/modules/battery/BatteryDispatcher.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..010413386cf17c1fc339e1d5e2915b9072f7b9b6
--- /dev/null
+++ b/Source/modules/battery/BatteryDispatcher.cpp
@@ -0,0 +1,96 @@
+// 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.
+
+#include "config.h"
+#include "modules/battery/BatteryDispatcher.h"
+
+#include "core/events/Event.h"
+#include "modules/battery/BatteryStatus.h"
+#include "platform/NotImplemented.h"
+#include "public/platform/Platform.h"
+
+namespace WebCore {
+
+BatteryDispatcher& BatteryDispatcher::instance()
+{
+    DEFINE_STATIC_LOCAL(BatteryDispatcher, batteryDispatcher, ());
+    return batteryDispatcher;
+}
+
+BatteryDispatcher::BatteryDispatcher()
+{
+}
+
+BatteryDispatcher::~BatteryDispatcher()
+{
+}
+
+void BatteryDispatcher::addClient(BatteryManager* batteryManager)
+{
+    addController(batteryManager);
+}
+
+void BatteryDispatcher::removeClient(BatteryManager* batteryManager)
+{
+    removeController(batteryManager);
+}
+
+void BatteryDispatcher::updateBatteryStatus(const blink::WebBatteryStatus& batteryStatus)
+{
+    RefPtr<BatteryStatus> oldStatus = m_batteryStatus;
+    m_batteryStatus = BatteryStatus::create(batteryStatus.charging, batteryStatus.chargingTime, batteryStatus.dischargingTime, batteryStatus.level);
+
+    if (oldStatus) {
+        if (m_batteryStatus->charging() != oldStatus->charging())
+            didChangeBatteryStatus(EventTypeNames::chargingchange);
+        if (m_batteryStatus->charging() && m_batteryStatus->chargingTime() != oldStatus->chargingTime())
+            didChangeBatteryStatus(EventTypeNames::chargingtimechange);
+        if (!m_batteryStatus->charging() && m_batteryStatus->dischargingTime() != oldStatus->dischargingTime())
+            didChangeBatteryStatus(EventTypeNames::dischargingtimechange);
+        if (m_batteryStatus->level() != oldStatus->level())
+            didChangeBatteryStatus(EventTypeNames::levelchange);
+    } else {
+        // There was no previous state.
+        didChangeBatteryStatus(EventTypeNames::chargingchange);
+        didChangeBatteryStatus(EventTypeNames::chargingtimechange);
+        didChangeBatteryStatus(EventTypeNames::dischargingtimechange);
+        didChangeBatteryStatus(EventTypeNames::levelchange);
+    }
+
+}
+
+const BatteryStatus* BatteryDispatcher::getLatestData()
+{
+    return m_batteryStatus.get();
+}
+
+void BatteryDispatcher::didChangeBatteryStatus(const AtomicString& eventType)
+{
+    RefPtrWillBeRawPtr<Event> event = Event::create(eventType);
+
+    {
+        TemporaryChange<bool> changeIsDispatching(m_isDispatching, true);
+        // Don't fire listeners removed or added during event dispatch.
+        size_t size = m_controllers.size();
+        for (size_t i = 0; i < size; ++i) {
+            if (m_controllers[i])
+                static_cast<BatteryManager*>(m_controllers[i])->didChangeBatteryStatus(event);
+        }
+    }
+
+    if (m_needsPurge)
+        purgeControllers();
+}
+
+void BatteryDispatcher::startListening()
+{
+    notImplemented();
+}
+
+void BatteryDispatcher::stopListening()
+{
+    notImplemented();
+}
+
+}