OverscrollGlow for mainThread-{BLINK CHANGES}

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 215 matching lines @@
     , m_selectionInitiationState(HaveNotStartedSelection)
     , m_hoverTimer(this, &EventHandler::hoverTimerFired)
     , m_cursorUpdateTimer(this, &EventHandler::cursorUpdateTimerFired)
     , m_mouseDownMayStartAutoscroll(false)
     , m_fakeMouseMoveEventTimer(this, &EventHandler::fakeMouseMoveEventTimerFired)
     , m_svgPan(false)
     , m_resizeScrollableArea(nullptr)
     , m_eventHandlerWillResetCapturingMouseEventsNode(0)
     , m_clickCount(0)
     , m_shouldOnlyFireDragOverEvent(false)
+    , m_unusedDelta(FloatSize())
+    , m_accumulatedRootOverscroll(FloatSize())
     , m_mousePositionIsUnknown(true)
     , m_mouseDownTimestamp(0)
     , m_widgetIsLatched(false)
     , m_touchPressed(false)
     , m_scrollGestureHandlingNode(nullptr)
     , m_lastGestureScrollOverWidget(false)
     , m_maxMouseMovedDuration(0)
     , m_longTapShouldInvokeContextMenu(false)
     , m_activeIntervalTimer(this, &EventHandler::activeIntervalTimerFired)
     , m_lastShowPressTimestamp(0)
@@ skipping 673 matching lines @@
 
     return result;
 }
 
 void EventHandler::stopAutoscroll()
 {
     if (AutoscrollController* controller = autoscrollController())
         controller->stopAutoscroll();
 }
 
-bool EventHandler::scroll(ScrollDirection direction, ScrollGranularity granularity, Node* startNode, Node** stopNode, float delta, IntPoint absolutePoint)
+ScrollResultOneDimensional EventHandler::scroll(ScrollDirection direction, ScrollGranularity granularity, Node* startNode, Node** stopNode, float delta, IntPoint absolutePoint)
 {
     if (!delta)
-        return false;
+        return ScrollResultOneDimensional(false);
 
     Node* node = startNode;
 
     if (!node)
         node = m_frame->document()->focusedElement();
 
     if (!node)
         node = m_mousePressNode.get();
 
     if (!node || !node->layoutObject())
-        return false;
+        return ScrollResultOneDimensional(false, delta);
 
     bool rootLayerScrolls = m_frame->settings() && m_frame->settings()->rootLayerScrolls();
     LayoutBox* curBox = node->layoutObject()->enclosingBox();
+    ScrollResultOneDimensional result(false, delta);
     while (curBox && (rootLayerScrolls || !curBox->isLayoutView())) {
         ScrollDirection physicalDirection = toPhysicalDirection(
             direction, curBox->isHorizontalWritingMode(), curBox->style()->isFlippedBlocksWritingMode());
 
         // If we're at the stopNode, we should try to scroll it but we shouldn't bubble past it
         bool shouldStopBubbling = stopNode && *stopNode && curBox->node() == *stopNode;
-        bool didScroll = curBox->scroll(physicalDirection, granularity, delta);
+        result = curBox->scroll(physicalDirection, granularity, delta);
 
-        if (didScroll && stopNode)
+        if (result.didScroll && stopNode)
             *stopNode = curBox->node();
 
-        if (didScroll || shouldStopBubbling) {
+        if (result.didScroll || shouldStopBubbling) {
             setFrameWasScrolledByUser();
-            return true;
+            return result;

[majidvp, 2015/05/07 16:35:30]

This no longer guarantee that we return 'true' here.
Note that when shouldStopBubbling is set we should always return true to avoid
scroll event to bubble up to next frame.

Please update to match the existing logic.

[MuVen, 2015/05/13 16:55:46]

Done.

         }
 
         curBox = curBox->containingBlock();
     }
 
-    return false;
+    return result;
 }
 
 void EventHandler::customizedScroll(const Node& startNode, ScrollState& scrollState)
 {
     if (scrollState.fullyConsumed())
         return;
 
     if (m_currentScrollChain.isEmpty())
         recomputeScrollChain(*m_frame, startNode, m_currentScrollChain);
     scrollState.setScrollChain(m_currentScrollChain);
     scrollState.distributeToScrollChainDescendant();
 }
 
 bool EventHandler::bubblingScroll(ScrollDirection direction, ScrollGranularity granularity, Node* startingNode)
 {
     // The layout needs to be up to date to determine if we can scroll. We may be
     // here because of an onLoad event, in which case the final layout hasn't been performed yet.
     m_frame->document()->updateLayoutIgnorePendingStylesheets();
     // FIXME: enable scroll customization in this case. See crbug.com/410974.
-    if (scroll(direction, granularity, startingNode))
+    if (scroll(direction, granularity, startingNode).didScroll)
         return true;
     LocalFrame* frame = m_frame;
     FrameView* view = frame->view();
     if (view && view->scroll(direction, granularity))
         return true;
     Frame* parentFrame = frame->tree().parent();
     if (!parentFrame || !parentFrame->isLocalFrame())
         return false;
     // FIXME: Broken for OOPI.
     return toLocalFrame(parentFrame)->eventHandler().bubblingScroll(direction, granularity, m_frame->deprecatedLocalOwner());
@@ skipping 1200 matching lines @@
 
     Node* stopNode = m_previousWheelScrolledNode.get();
     ScrollGranularity granularity = wheelGranularityToScrollGranularity(wheelEvent);
     IntPoint absolutePosition = roundedIntPoint(wheelEvent->absoluteLocation());
 
     // Break up into two scrolls if we need to.  Diagonal movement on
     // a MacBook pro is an example of a 2-dimensional mouse wheel event (where both deltaX and deltaY can be set).
 
     // FIXME: enable scroll customization in this case. See crbug.com/410974.
     if (wheelEvent->railsMode() != Event::RailsModeVertical
-        && scroll(ScrollRight, granularity, startNode, &stopNode, wheelEvent->deltaX(), absolutePosition))
+        && scroll(ScrollRight, granularity, startNode, &stopNode, wheelEvent->deltaX(), absolutePosition).didScroll)
         wheelEvent->setDefaultHandled();
 
     if (wheelEvent->railsMode() != Event::RailsModeHorizontal
-        && scroll(ScrollDown, granularity, startNode, &stopNode, wheelEvent->deltaY(), absolutePosition))
+        && scroll(ScrollDown, granularity, startNode, &stopNode, wheelEvent->deltaY(), absolutePosition).didScroll)
         wheelEvent->setDefaultHandled();
 
     if (!m_latchedWheelEventNode)
         m_previousWheelScrolledNode = stopNode;
 }
 
 bool EventHandler::handleGestureShowPress()
 {
     m_lastShowPressTimestamp = WTF::currentTime();
 
@@ skipping 480 matching lines @@
             m_previousGestureScrolledNode = scrollState->currentNativeScrollingElement();
             m_deltaConsumedForScrollSequence = scrollState->deltaConsumedForScrollSequence();
             scrolled = scrollState->deltaX() != gestureEvent.deltaX()
                 || scrollState->deltaY() != gestureEvent.deltaY();
         } else {
             if (gestureEvent.preventPropagation())
                 stopNode = m_previousGestureScrolledNode.get();
 
             // First try to scroll the closest scrollable LayoutBox ancestor of |node|.
             ScrollGranularity granularity = ScrollByPrecisePixel;
-            bool horizontalScroll = scroll(ScrollLeft, granularity, node, &stopNode, delta.width());
+            m_unusedDelta = FloatSize();
+            ScrollResultOneDimensional result = scroll(ScrollLeft, granularity, node, &stopNode, delta.width());
+            bool horizontalScroll = result.didScroll;
+            if (m_frame->isMainFrame())
+                m_unusedDelta.setWidth(result.unusedScrollDelta);

[majidvp, 2015/05/07 16:35:29]

Compositor overscroll logic only collects overscroll when the root layer on of
the mainframe has unused delta. This logic collects unused delta from any scroll
even if it is not root layer that scrolls.

You should match CC behaviour. See here:
https://code.google.com/p/chromium/codesearch#chromium/src/cc/trees/layer_tre...

Perhaps EventHandler::scroll shouldn't return any unused scroll delta by only
unused _root_ scroll delta. This makes it more consistent with CC
implementation.

Please make sure this behaviour is captured in the test.

[MuVen, 2015/05/13 16:55:46]

Done.

             if (!gestureEvent.preventPropagation())
                 stopNode = nullptr;
-            bool verticalScroll = scroll(ScrollUp, granularity, node, &stopNode, delta.height());
+            result = scroll(ScrollUp, granularity, node, &stopNode, delta.height());
+            bool verticalScroll = result.didScroll;
+            if (m_frame->isMainFrame())
+                m_unusedDelta.setHeight(result.unusedScrollDelta);
             scrolled = horizontalScroll || verticalScroll;
 
             if (gestureEvent.preventPropagation())
                 m_previousGestureScrolledNode = stopNode;
+
+            if (m_frame->isMainFrame())

[majidvp, 2015/05/07 16:35:30]

mainframe check here is redundant. For non mainframe the unused delta is 0.

[MuVen, 2015/05/13 16:55:46]

Done.

+                m_accumulatedRootOverscroll += m_unusedDelta;
+
+            if (m_frame->isMainFrame() && m_unusedDelta != FloatSize()) {

[majidvp, 2015/05/07 16:35:30]

Again mainframe check is redundant.

[MuVen, 2015/05/13 16:55:46]

Done.

+                FloatPoint position = FloatPoint(gestureEvent.position().x(), gestureEvent.position().y());
+                FloatSize velocity = FloatSize(gestureEvent.velocityX(), gestureEvent.velocityY());
+                m_frame->chromeClient().didOverscroll(m_unusedDelta, m_accumulatedRootOverscroll, position, velocity);
+            }
         }
         if (scrolled) {
             setFrameWasScrolledByUser();
             return true;
         }
     }
 
     if (RuntimeEnabledFeatures::scrollCustomizationEnabled())
         return false;
 
     // Try to scroll the frame view.
     if (m_frame->applyScrollDelta(delta, false)) {
         setFrameWasScrolledByUser();
         return true;
     }
 
     return false;
 }
 
 void EventHandler::clearGestureScrollNodes()
 {
     m_scrollGestureHandlingNode = nullptr;
     m_previousGestureScrolledNode = nullptr;
     m_deltaConsumedForScrollSequence = false;
     m_currentScrollChain.clear();
+    m_accumulatedRootOverscroll = FloatSize();

[majidvp, 2015/05/07 16:35:30]

This clears accumulated root overscroll only at the end of scroll gesture which
is not enough.

The overscroll amount should also get reset every time we can successfully
scroll which could happen during the same gesture.

See:
https://code.google.com/p/chromium/codesearch#chromium/src/cc/trees/layer_tre...

Please make sure this is captured in the test.

[MuVen, 2015/05/13 16:55:46]

Done.

 }
 
 bool EventHandler::isScrollbarHandlingGestures() const
 {
     return m_scrollbarHandlingScrollGesture.get();
 }
 
 bool EventHandler::shouldApplyTouchAdjustment(const PlatformGestureEvent& event) const
 {
     if (m_frame->settings() && !m_frame->settings()->touchAdjustmentEnabled())
@@ skipping 863 matching lines @@
 
 void EventHandler::defaultSpaceEventHandler(KeyboardEvent* event)
 {
     ASSERT(event->type() == EventTypeNames::keypress);
 
     if (event->ctrlKey() || event->metaKey() || event->altKey())
         return;
 
     ScrollDirection direction = event->shiftKey() ? ScrollBlockDirectionBackward : ScrollBlockDirectionForward;
     // FIXME: enable scroll customization in this case. See crbug.com/410974.
-    if (scroll(direction, ScrollByPage)) {
+    if (scroll(direction, ScrollByPage).didScroll) {
         event->setDefaultHandled();
         return;
     }
 
     FrameView* view = m_frame->view();
     if (!view)
         return;
 
     if (view->scroll(direction, ScrollByPage))
         event->setDefaultHandled();
@@ skipping 497 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink