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Commit 6d9bba7b authored by abarth@chromium.org's avatar abarth@chromium.org
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Non-composited, fixed position should trigger main thread scrolling 

In a recent change, I broke the logic for determining whether fixed position
elements should trigger main thread scrolling. This CL fixes the logic to
trigger main thread scrolling if we have fixed position elements that lack
composited layers.

R=vollick@chromium.org
BUG=402359

Review URL: https://codereview.chromium.org/465333004

git-svn-id: svn://svn.chromium.org/blink/trunk@180226 bbb929c8-8fbe-4397-9dbb-9b2b20218538
parent 96c40ae3
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Showing with 68 additions and 16 deletions
third_party/WebKit/LayoutTests/compositing/layer-creation/main-thread-scrolling-for-non-composited-fixed-position-expected.txt 0 → 100644
View file @ 6d9bba7b
TEST
{
"bounds": [800, 600],
"children": [
{
"bounds": [800, 600],
"contentsOpaque": true,
"drawsContent": true
}
]
}
Has non-layer viewport-constrained objects
third_party/WebKit/LayoutTests/compositing/layer-creation/main-thread-scrolling-for-non-composited-fixed-position.html 0 → 100644
View file @ 6d9bba7b
<!DOCTYPE html>
<html>
<head>
<style>
.fixed {
position: fixed;
left: 10px;
top: 10px;
}
</style>
<script>
if (window.internals)
window.internals.settings.setAcceleratedCompositingForFixedPositionEnabled(false);
if (window.testRunner) {
testRunner.dumpAsText();
window.addEventListener("load", function() {
document.getElementById("layerTree").innerText = window.internals.layerTreeAsText(document);
document.getElementById("mainThreadScrollingReasons").innerText = window.internals.mainThreadScrollingReasons(document);
}, false);
}
</script>
</head>
<body>
<div class="fixed">TEST</div>
<pre id="layerTree"></pre>
<pre id="mainThreadScrollingReasons"></pre>
</body>
</html>
third_party/WebKit/Source/core/page/scrolling/ScrollingCoordinator.cpp
View file @ 6d9bba7b
......@@ -887,13 +887,23 @@ bool ScrollingCoordinator::hasVisibleSlowRepaintViewportConstrainedObjects(Frame
return false;
for (FrameView::ViewportConstrainedObjectSet::const_iterator it = viewportConstrainedObjects->begin(), end = viewportConstrainedObjects->end(); it != end; ++it) {
RenderObject* viewportConstrainedObject = *it;
if (!viewportConstrainedObject->isBoxModelObject() || !viewportConstrainedObject->hasLayer())
return true;
RenderLayer* layer = toRenderBoxModelObject(viewportConstrainedObject)->layer();
// Composited layers that actually paint into their enclosing ancestor
// must also force main thread scrolling.
if (layer->compositingState() == HasOwnBackingButPaintsIntoAncestor)
RenderObject* renderer = *it;
ASSERT(renderer->isBoxModelObject() && renderer->hasLayer());
ASSERT(renderer->style()->position() == FixedPosition);
RenderLayer* layer = toRenderBoxModelObject(renderer)->layer();
// Whether the RenderLayer scrolls with the viewport is a tree-depenent
// property and our viewportConstrainedObjects collection is maintained
// with only RenderObject-level information.
if (!layer->scrollsWithViewport())
continue;
// We're only smart enough to scroll viewport-constrainted objects
// in the compositor if they have their own backing or they paint
// into a grouped back (which necessarily all have the same viewport
// constraints).
CompositingState compositingState = layer->compositingState();
if (compositingState != PaintsIntoOwnBacking && compositingState != PaintsIntoGroupedBacking)
return true;
}
return false;
......
third_party/WebKit/Source/core/rendering/RenderLayer.cpp
View file @ 6d9bba7b
......@@ -305,7 +305,7 @@ void RenderLayer::dirtyAncestorChainHasSelfPaintingLayerDescendantStatus()
bool RenderLayer::scrollsWithViewport() const
{
return renderer()->style()->position() == FixedPosition && renderer()->containingBlock()->enclosingLayer()->isRootLayer();
return renderer()->style()->position() == FixedPosition && renderer()->containerForFixedPosition() == renderer()->view();
}
bool RenderLayer::scrollsWithRespectTo(const RenderLayer* other) const
......
third_party/WebKit/Source/core/rendering/RenderObject.h
View file @ 6d9bba7b
......@@ -656,6 +656,7 @@ public:
// If paintInvalidationContainer and paintInvalidationContainerSkipped are not null, on return *paintInvalidationContainerSkipped
// is true if the renderer returned is an ancestor of paintInvalidationContainer.
RenderObject* container(const RenderLayerModelObject* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;
RenderBlock* containerForFixedPosition(const RenderLayerModelObject* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;
virtual RenderObject* hoverAncestor() const { return parent(); }
......@@ -1158,8 +1159,6 @@ protected:
private:
const RenderLayerModelObject* enclosingCompositedContainer() const;
RenderBlock* containerForFixedPosition(const RenderLayerModelObject* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;
RenderFlowThread* locateFlowThreadContainingBlock() const;
void removeFromRenderFlowThread();
void removeFromRenderFlowThreadRecursive(RenderFlowThread*);
......
third_party/WebKit/Source/core/rendering/compositing/CompositingReasonFinder.cpp
View file @ 6d9bba7b
......@@ -149,7 +149,7 @@ CompositingReasons CompositingReasonFinder::nonStyleDeterminedDirectReasons(cons
directReasons |= CompositingReasonOverflowScrollingTouch;
}
if (requiresCompositingForPositionFixed(renderer))
if (requiresCompositingForPositionFixed(layer))
directReasons |= CompositingReasonPositionFixed;
directReasons |= renderer->additionalCompositingReasons();
......@@ -166,15 +166,13 @@ bool CompositingReasonFinder::requiresCompositingForAnimation(RenderStyle* style
return style->shouldCompositeForCurrentAnimations();
}
bool CompositingReasonFinder::requiresCompositingForPositionFixed(RenderObject* renderer) const
bool CompositingReasonFinder::requiresCompositingForPositionFixed(const RenderLayer* layer) const
{
if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger))
return false;
// Don't promote fixed position elements that are descendants of a non-view container, e.g. transformed elements.
// They will stay fixed wrt the container rather than the enclosing frame.
return renderer->style()->position() == FixedPosition
&& renderer->container() == &m_renderView
&& m_renderView.frameView()->isScrollable();
return layer->scrollsWithViewport() && m_renderView.frameView()->isScrollable();
}
}
third_party/WebKit/Source/core/rendering/compositing/CompositingReasonFinder.h
View file @ 6d9bba7b
......@@ -34,7 +34,7 @@ private:
bool requiresCompositingForTransform(RenderObject*) const;
bool requiresCompositingForAnimation(RenderStyle*) const;
bool requiresCompositingForPositionFixed(RenderObject*) const;
bool requiresCompositingForPositionFixed(const RenderLayer*) const;
RenderView& m_renderView;
CompositingTriggerFlags m_compositingTriggers;
......
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