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

Source/modules/device_light/DeviceLightDispatcher.cpp

Index: Source/modules/device_light/DeviceLightDispatcher.cpp
diff --git a/Source/modules/device_light/DeviceLightDispatcher.cpp b/Source/modules/device_light/DeviceLightDispatcher.cpp
index ed0b32f440d79863c110cd35ae796445c7559c64..f692131b1a52415413cac7d72ddf535e2363d918 100644
--- a/Source/modules/device_light/DeviceLightDispatcher.cpp
+++ b/Source/modules/device_light/DeviceLightDispatcher.cpp
@@ -8,6 +8,7 @@
 #include "core/frame/DeviceSensorEventDispatcher.h"
 #include "modules/device_light/DeviceLightController.h"
 #include "public/platform/Platform.h"
+#include "wtf/TemporaryChange.h"
 
 namespace WebCore {
 
@@ -26,6 +27,17 @@
 {
 }
 
+
+void DeviceLightDispatcher::addDeviceLightController(DeviceLightController* controller)
+{
+    addController(controller);
+}
+
+void DeviceLightDispatcher::removeDeviceLightController(DeviceLightController* controller)
+{
+    removeController(controller);
+}
+
 void DeviceLightDispatcher::startListening()
 {
     blink::Platform::current()->setDeviceLightListener(this);
@@ -40,7 +52,19 @@
 void DeviceLightDispatcher::didChangeDeviceLight(double value)
 {
     m_lastDeviceLightData = value;
-    notifyControllers();
+
+    {
+        TemporaryChange<bool> changeIsDispatching(m_isDispatching, true);
+        // Don't fire controllers 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<DeviceLightController*>(m_controllers[i])->didChangeDeviceLight(m_lastDeviceLightData);
+        }
+    }
+
+    if (m_needsPurge)
+        purgeControllers();
 }
 
 double DeviceLightDispatcher::latestDeviceLightData() const