Add RAPPOR metric recording for Device{Orientation,Motion} in blink.

Source/modules/device_orientation/DeviceOrientationController.cpp

Index: Source/modules/device_orientation/DeviceOrientationController.cpp
diff --git a/Source/modules/device_orientation/DeviceOrientationController.cpp b/Source/modules/device_orientation/DeviceOrientationController.cpp
index a08d7fdd2f7f7117ed4f494a16c0552c7c523f15..0d24ba1255386aa32ea94858a975f317f1af602e 100644
--- a/Source/modules/device_orientation/DeviceOrientationController.cpp
+++ b/Source/modules/device_orientation/DeviceOrientationController.cpp
@@ -13,6 +13,7 @@
 #include "modules/device_orientation/DeviceOrientationDispatcher.h"
 #include "modules/device_orientation/DeviceOrientationEvent.h"
 #include "platform/weborigin/SecurityOrigin.h"
+#include "public/platform/Platform.h"
 
 namespace blink {
 
@@ -66,6 +67,9 @@ void DeviceOrientationController::didAddEventListener(LocalDOMWindow* window, co
         }
     }
 
+    if (!m_hasEventListener)
+        Platform::current()->recordRapporMetric(WebPlatformEventDeviceOrientation, WebURL(document().url()));
+
     DeviceSingleWindowEventController::didAddEventListener(window, eventType);
 }