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

Source/core/html/shadow/SpinButtonElement.h

Index: Source/core/html/shadow/SpinButtonElement.h
diff --git a/Source/core/html/shadow/SpinButtonElement.h b/Source/core/html/shadow/SpinButtonElement.h
index 8c3da22f80948b513f6812ddfe125be08c9e78c1..5ca24d44871e26cbd8ee81ef4c1231a434155f30 100644
--- a/Source/core/html/shadow/SpinButtonElement.h
+++ b/Source/core/html/shadow/SpinButtonElement.h
@@ -47,6 +47,7 @@ public:
         virtual void focusAndSelectSpinButtonOwner() = 0;
         virtual bool shouldSpinButtonRespondToMouseEvents() = 0;
         virtual bool shouldSpinButtonRespondToWheelEvents() = 0;
+        virtual void spinButtonDidReleaseMouseCapture() = 0;
         virtual void spinButtonStepDown() = 0;
         virtual void spinButtonStepUp() = 0;
     };
@@ -69,7 +70,6 @@ public:
 private:
     SpinButtonElement(Document&, SpinButtonOwner&);
 
-    virtual void detach(const AttachContext& = AttachContext()) OVERRIDE;
     virtual bool isSpinButtonElement() const OVERRIDE { return true; }
     virtual bool isDisabledFormControl() const OVERRIDE { return shadowHost() && shadowHost()->isDisabledFormControl(); }
     virtual bool matchesReadOnlyPseudoClass() const OVERRIDE;