Move viewport actions into an ApplyScroll callback.

third_party/WebKit/Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 131 matching lines @@
 
 // We need to retain the scroll customization callbacks until the element
 // they're associated with is destroyed. It would be simplest if the callbacks
 // could be stored in ElementRareData, but we can't afford the space
 // increase. Instead, keep the scroll customization callbacks here. The other
 // option would be to store these callbacks on the FrameHost or document, but
 // that necessitates a bunch more logic for transferring the callbacks between
 // FrameHosts when elements are moved around.
 ScrollCustomizationCallbacks& scrollCustomizationCallbacks()
 {
-    DCHECK(RuntimeEnabledFeatures::scrollCustomizationEnabled());
     DEFINE_STATIC_LOCAL(ScrollCustomizationCallbacks, scrollCustomizationCallbacks, (new ScrollCustomizationCallbacks));
     return scrollCustomizationCallbacks;
 }
 
 } // namespace
 
 using namespace HTMLNames;
 using namespace XMLNames;
 
 enum class ClassStringContent { Empty, WhiteSpaceOnly, HasClasses };
@@ skipping 336 matching lines @@
     scrollStateCallback->setNativeScrollBehavior(ScrollStateCallback::toNativeScrollBehavior(nativeScrollBehavior));
     scrollCustomizationCallbacks().setDistributeScroll(this, scrollStateCallback);
 }
 
 void Element::setApplyScroll(ScrollStateCallback* scrollStateCallback, String nativeScrollBehavior)
 {
     scrollStateCallback->setNativeScrollBehavior(ScrollStateCallback::toNativeScrollBehavior(nativeScrollBehavior));
     scrollCustomizationCallbacks().setApplyScroll(this, scrollStateCallback);
 }
 
+void Element::removeApplyScroll()
+{
+    scrollCustomizationCallbacks().removeApplyScroll(this);
+}
+
+ScrollStateCallback* Element::getApplyScroll()
+{
+    return scrollCustomizationCallbacks().getApplyScroll(this);
+}
+
 void Element::nativeDistributeScroll(ScrollState& scrollState)
 {
-    DCHECK(RuntimeEnabledFeatures::scrollCustomizationEnabled());
     if (scrollState.fullyConsumed())
         return;
 
     scrollState.distributeToScrollChainDescendant();
 
     // If the scroll doesn't propagate, and we're currently scrolling
     // an element other than this one, prevent the scroll from
     // propagating to this element.
     if (!scrollState.shouldPropagate()
         && scrollState.deltaConsumedForScrollSequence()
@@ skipping 21 matching lines @@
         callback->handleEvent(&scrollState);
     if (callback->nativeScrollBehavior() != WebNativeScrollBehavior::DisableNativeScroll)
         nativeDistributeScroll(scrollState);
     if (callback->nativeScrollBehavior() == WebNativeScrollBehavior::PerformAfterNativeScroll)
         callback->handleEvent(&scrollState);
 };
 
 void Element::nativeApplyScroll(ScrollState& scrollState)
 {
     DCHECK(RuntimeEnabledFeatures::scrollCustomizationEnabled());
+
+    // All elements in the scroll chain should be boxes.
+    DCHECK(!layoutObject() || layoutObject()->isBox());
+
     if (scrollState.fullyConsumed())
         return;
 
-    const double deltaX = scrollState.deltaX();
-    const double deltaY = scrollState.deltaY();
-    bool scrolled = false;
+    FloatSize delta(scrollState.deltaX(), scrollState.deltaY());
+
+    if (delta.isZero())
+        return;
 
     // TODO(esprehn): This should use updateLayoutIgnorePendingStylesheetsForNode.
-    if (deltaY || deltaX)
-        document().updateLayoutIgnorePendingStylesheets();
+    document().updateLayoutIgnorePendingStylesheets();
 
-    // Handle the scrollingElement separately, as it scrolls the viewport.
-    if (this == document().scrollingElement()) {
-        FloatSize delta(deltaX, deltaY);
-        if (document().frame()->applyScrollDelta(ScrollByPrecisePixel, delta, scrollState.isBeginning()).didScroll()) {
-            scrolled = true;
-            scrollState.consumeDeltaNative(scrollState.deltaX(), scrollState.deltaY());
-        }
-    } else {
-        if (!layoutObject())
-            return;
-        LayoutBoxItem curBox = LayoutBoxItem(toLayoutBox(layoutObject())).enclosingBox();
-        // FIXME: Native scrollers should only consume the scroll they
-        // apply. See crbug.com/457765.
-        if (deltaX && curBox.scroll(ScrollByPrecisePixel, FloatSize(deltaX, 0)).didScrollX) {
-            scrollState.consumeDeltaNative(scrollState.deltaX(), 0);
-            scrolled = true;
-        }
+    LayoutBox* boxToScroll = nullptr;
 
-        if (deltaY && curBox.scroll(ScrollByPrecisePixel, FloatSize(0, deltaY)).didScrollY) {
-            scrollState.consumeDeltaNative(0, scrollState.deltaY());
-            scrolled = true;
-        }
-    }
+    // Handle the scrollingElement separately, as it should scroll the viewport.
+    if (this == document().scrollingElement())
+        boxToScroll = document().layoutView();
+    else if (layoutObject())
+        boxToScroll = toLayoutBox(layoutObject());
 
-    if (!scrolled)
+    if (!boxToScroll)
         return;
 
+    ScrollResult result =
+        LayoutBoxItem(boxToScroll).enclosingBox().scroll(
+            ScrollByPrecisePixel,
+            delta);
+
+    if (!result.didScroll())
+        return;
+
+    // FIXME: Native scrollers should only consume the scroll they
+    // apply. See crbug.com/457765.
+    scrollState.consumeDeltaNative(delta.width(), delta.height());
+
     // We need to setCurrentNativeScrollingElement in both the
     // distributeScroll and applyScroll default implementations so
     // that if JS overrides one of these methods, but not the
     // other, this bookkeeping remains accurate.
     scrollState.setCurrentNativeScrollingElement(this);
     if (scrollState.fromUserInput()) {
         if (DocumentLoader* documentLoader = document().loader())
             documentLoader->initialScrollState().wasScrolledByUser = true;
     }
 };
@@ skipping 3088 matching lines @@
 
 DEFINE_TRACE(Element)
 {
     if (hasRareData())
         visitor->trace(elementRareData());
     visitor->trace(m_elementData);
     ContainerNode::trace(visitor);
 }
 
 } // namespace blink