Implement DeviceLight

Source/modules/device_light/DeviceLightController.cpp

+// 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/device_light/DeviceLightController.h"
+
+#include "RuntimeEnabledFeatures.h"
+#include "core/dom/Document.h"
+#include "core/events/ThreadLocalEventNames.h"
+#include "core/frame/DeviceSensorEventController.h"
+#include "core/page/Page.h"
+#include "modules/device_light/DeviceLightDispatcher.h"
+#include "modules/device_light/DeviceLightEvent.h"
+
+namespace WebCore {
+
+DeviceLightController::DeviceLightController(Document& document)
+    : DeviceSensorEventController(document)
+    , DOMWindowLifecycleObserver(document.domWindow())
+{
+}
+
+DeviceLightController::~DeviceLightController()
+{
+    stopUpdating();
+}
+
+void DeviceLightController::didChangeDeviceLight(double value)
+{
+    dispatchDeviceEvent(DeviceLightEvent::create(EventTypeNames::devicelight, value));
+}
+
+const char* DeviceLightController::supplementName()
+{
+    return "DeviceLightController";
+}
+
+DeviceLightController& DeviceLightController::from(Document& document)
+{
+    DeviceLightController* controller = static_cast<DeviceLightController*>(DocumentSupplement::from(document, supplementName()));
+    if (!controller) {
+        controller = new DeviceLightController(document);
+        DocumentSupplement::provideTo(document, supplementName(), adoptPtr(controller));
+    }
+    return *controller;
+}
+
+bool DeviceLightController::hasLastData()
+{
+    return DeviceLightDispatcher::instance().latestDeviceLightData();
+}
+
+PassRefPtr<Event> DeviceLightController::getLastEvent()
+{
+    return DeviceLightEvent::create(EventTypeNames::devicelight,
+        DeviceLightDispatcher::instance().latestDeviceLightData());
+}
+
+void DeviceLightController::registerWithDispatcher()
+{
+    DeviceLightDispatcher::instance().addDeviceLightController(this);
+}
+
+void DeviceLightController::unregisterWithDispatcher()
+{
+    DeviceLightDispatcher::instance().removeDeviceLightController(this);
+}
+
+bool DeviceLightController::isNullEvent(Event* event)
+{
+    DeviceLightEvent* lightEvent = toDeviceLightEvent(event);
+    return !lightEvent->value();
+}
+
+void DeviceLightController::didAddEventListener(DOMWindow* window, const AtomicString& eventType)
+{
+    if (eventType == EventTypeNames::devicelight && RuntimeEnabledFeatures::deviceLightEnabled()) {
+        if (page() && page()->visibilityState() == PageVisibilityStateVisible)
+            startUpdating();

[abarth-chromium, 2014/03/18 22:48:53]

What happens when visibilityState() changes?  Don't we need to start updating
then?

[riju_, 2014/03/19 12:28:13]

My understanding is that, we update only if the page is visible. That is the
case with the other apis.

+        m_hasEventListener = true;
+    }
+}
+
+void DeviceLightController::didRemoveEventListener(DOMWindow* window, const AtomicString& eventType)
+{
+    if (eventType == EventTypeNames::devicelight) {
+        stopUpdating();
+        m_hasEventListener = false;
+    }
+}
+
+void DeviceLightController::didRemoveAllEventListeners(DOMWindow* window)
+{
+    stopUpdating();
+    m_hasEventListener = false;
+}
+
+
+} // namespace WebCore