Allow postponed rail application for touch scrolling - blink side.

Source/core/page/EventHandler.cpp

Index: Source/core/page/EventHandler.cpp
diff --git a/Source/core/page/EventHandler.cpp b/Source/core/page/EventHandler.cpp
index 7a6b2740d320eb8558180654e6aa6c0a02c0ce8d..e3e2df14328dadcccf1ca5f175c85f18700f2380 100644
--- a/Source/core/page/EventHandler.cpp
+++ b/Source/core/page/EventHandler.cpp
@@ -2569,8 +2569,12 @@ bool EventHandler::handleGestureScrollBegin(const PlatformGestureEvent& gestureE
 bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gestureEvent)
 {
     ASSERT(gestureEvent.type() == PlatformEvent::GestureScrollUpdate);
-
-    FloatSize delta(gestureEvent.deltaX(), gestureEvent.deltaY());
+    bool ignoreX = gestureEvent.railsMode() == PlatformEvent::RailsModeVertical;
+    bool ignoreY = gestureEvent.railsMode() == PlatformEvent::RailsModeHorizontal;
+    FloatSize delta(ignoreX ? 0 : gestureEvent.deltaX(),
+        ignoreY ? 0 : gestureEvent.deltaY());
+    FloatSize velocity(ignoreX ? 0 : gestureEvent.velocityX(),
+        ignoreY ? 0 : gestureEvent.velocityY());
     if (delta.isZero())
         return false;
 
@@ -2601,8 +2605,8 @@ bool EventHandler::handleGestureScrollUpdate(const PlatformGestureEvent& gesture
         bool scrolled = false;
         if (RuntimeEnabledFeatures::scrollCustomizationEnabled()) {
             RefPtrWillBeRawPtr<ScrollState> scrollState = ScrollState::create(
-                gestureEvent.deltaX(), gestureEvent.deltaY(),
-                0, gestureEvent.velocityX(), gestureEvent.velocityY(),
+                delta.width(), delta.height(),
+                0, velocity.width(), velocity.height(),
                 gestureEvent.inertial(), /* isBeginning */
                 false, /* isEnding */ false, /* fromUserInput */ true,
                 !gestureEvent.preventPropagation(), m_deltaConsumedForScrollSequence);