Do not dispatch 'change' events during pressing spin buttons for input[type=number].

Source/core/html/shadow/SpinButtonElement.cpp

Index: Source/core/html/shadow/SpinButtonElement.cpp
diff --git a/Source/core/html/shadow/SpinButtonElement.cpp b/Source/core/html/shadow/SpinButtonElement.cpp
index 22f4255e658a0f763186abbf5bdb8323c2437bd8..35833bdb1a7a2a4f2dfa8750c7b428e99e2bc0d8 100644
--- a/Source/core/html/shadow/SpinButtonElement.cpp
+++ b/Source/core/html/shadow/SpinButtonElement.cpp
@@ -60,12 +60,6 @@ PassRefPtr<SpinButtonElement> SpinButtonElement::create(Document& document, Spin
     return element.release();
 }
 
-void SpinButtonElement::detach(const AttachContext& context)
-{
-    releaseCapture();
-    HTMLDivElement::detach(context);
-}
-
 void SpinButtonElement::defaultEventHandler(Event* event)
 {
     if (!event->isMouseEvent()) {
@@ -106,12 +100,14 @@ void SpinButtonElement::defaultEventHandler(Event* event)
                     // chance to cancel the timer.
                     startRepeatingTimer();
                     doStepAction(m_upDownState == Up ? 1 : -1);
+                    if (m_spinButtonOwner)
+                        m_spinButtonOwner->spinButtonDidReleaseMouseCapture();

[tkent, 2014/04/07 04:31:17]

Why pinButtonDidReleaseMouseCapture is called?  We don't release mouse capture,
and we don't want to dispatch 'change' events on mousedown.

[Habib Virji, 2014/04/07 07:33:18]

Done.

                 }
             }
             event->setDefaultHandled();
         }
     } else if (mouseEvent->type() == EventTypeNames::mouseup && mouseEvent->button() == LeftButton) {
-        stopRepeatingTimer();
+        releaseCapture();
     } else if (event->type() == EventTypeNames::mousemove) {
         if (box->pixelSnappedBorderBoxRect().contains(local)) {
             if (!m_capturing) {
@@ -198,6 +194,9 @@ void SpinButtonElement::releaseCapture()
                 page->chrome().unregisterPopupOpeningObserver(this);
         }
     }
+    if (m_spinButtonOwner)
+        m_spinButtonOwner->spinButtonDidReleaseMouseCapture();
+
 }
 
 bool SpinButtonElement::matchesReadOnlyPseudoClass() const