Implement the Blink part of the Device Motion API.

Source/core/page/DOMWindow.cpp

Index: Source/core/page/DOMWindow.cpp
diff --git a/Source/core/page/DOMWindow.cpp b/Source/core/page/DOMWindow.cpp
index ad755343c9eedddb18cf26b774dd5360e803b51f..2ae40094a91ec4cf45e876cadf9902b235fd2e83 100644
--- a/Source/core/page/DOMWindow.cpp
+++ b/Source/core/page/DOMWindow.cpp
@@ -1537,8 +1537,8 @@ bool DOMWindow::addEventListener(const AtomicString& eventType, PassRefPtr<Event
     else if (eventType == eventNames().beforeunloadEvent && allowsBeforeUnloadListeners(this))
         addBeforeUnloadEventListener(this);
     else if (eventType == eventNames().devicemotionEvent && RuntimeEnabledFeatures::deviceMotionEnabled()) {
-        if (DeviceMotionController* controller = DeviceMotionController::from(page()))
-            controller->addDeviceEventListener(this);
+        if (DeviceMotionController* controller = DeviceMotionController::from(document()))

[Peter Beverloo, 2013/05/08 13:15:01]

I think it's confusing that you're passing document() here, while the
"devicemotion" event is available on the window object and has no relationship
to the document at all.

You supplement the device motion controller on ScriptExecutionContext, which is
a parent class of Document.  I don't think the DeviceMotionController should
know about Document at all, and we can instead just pass
DOMWindow::scriptExecutionContext().

The passed SEC will be identical to the one you're passing now so there won't be
any functional change, but I do think it's much cleaner.

[timvolodine, 2013/05/09 10:08:28]

hmm, the document is actually needed to dispatch the event to the window, I
haven't found any domWindow() method on the SEC.

[Peter Beverloo, 2013/05/09 11:31:38]

Right.  Now that we're no longer storing the DOMWindow in a RefPtr, I think it
would be fine to store a pointer to the DOMWindow instead of a pointer to
Document in DeviceMotionController.  You can get the script execution context
(activeDOMObjectsAre{Stopped,Suspended} et al) from DOMWindow as well.

Since the ScriptExecutionContext is owned by the DOMWindow this should be fine
in terms of lifetime as well.  What do you think?

+            controller->startUpdating();
     } else if (eventType == eventNames().deviceorientationEvent && RuntimeEnabledFeatures::deviceOrientationEnabled()) {
         if (DeviceOrientationController* controller = DeviceOrientationController::from(page()))
             controller->addDeviceEventListener(this);
@@ -1564,8 +1564,8 @@ bool DOMWindow::removeEventListener(const AtomicString& eventType, EventListener
     else if (eventType == eventNames().beforeunloadEvent && allowsBeforeUnloadListeners(this))
         removeBeforeUnloadEventListener(this);
     else if (eventType == eventNames().devicemotionEvent) {
-        if (DeviceMotionController* controller = DeviceMotionController::from(page()))
-            controller->removeDeviceEventListener(this);
+        if (DeviceMotionController* controller = DeviceMotionController::from(document()))
+            controller->stopUpdating();
     } else if (eventType == eventNames().deviceorientationEvent) {
         if (DeviceOrientationController* controller = DeviceOrientationController::from(page()))
             controller->removeDeviceEventListener(this);
@@ -1620,10 +1620,10 @@ void DOMWindow::removeAllEventListeners()
 {
     EventTarget::removeAllEventListeners();
 
-    if (DeviceMotionController* controller = DeviceMotionController::from(page()))
-        controller->removeAllDeviceEventListeners(this);
+    if (DeviceMotionController* controller = DeviceMotionController::from(document()))
+        controller->stopUpdating();
     if (DeviceOrientationController* controller = DeviceOrientationController::from(page()))
-        controller->removeAllDeviceEventListeners(this);
+        controller->removeDeviceEventListener(this);
     if (Document* document = this->document())
         document->didRemoveEventTargetNode(document);