Move PlatformEventDispatcher implementations to the Oilpan heap.

Source/modules/device_orientation/DeviceOrientationDispatcher.cpp

Index: Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
diff --git a/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp b/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
index 9b24851d369621eb80763bedb61755bc1a58a621..0880c3225f956aaa48f49030119bb0f124d1afd4 100644
--- a/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
+++ b/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
@@ -51,6 +51,12 @@ DeviceOrientationDispatcher::~DeviceOrientationDispatcher()
 {
 }
 
+void DeviceOrientationDispatcher::trace(Visitor* visitor)
+{
+    visitor->trace(m_lastDeviceOrientationData);
+    PlatformEventDispatcher::trace(visitor);
+}
+
 void DeviceOrientationDispatcher::startListening()
 {
     Platform::current()->startListening(WebPlatformEventDeviceOrientation, this);