Changeset 154417 in webkit

Timestamp:

Aug 21, 2013 2:32:41 PM (11 years ago)

Author:

Simon Fraser

Message:

<​https://webkit.org/b/116901> ASSERTION FAILED: !m_visibleDescendantStatusDirty on twitter

Reviewed by Beth Dakin.

In order to make decisions about compositing, the m_hasVisibleDescendant bit on RenderLayers
needs to be up-to-date when RenderLayerCompositor::computeCompositingRequirements is recursing
over the RenderLayer tree.

However, was possible for computeCompositingRequirements() to hit a layer whose m_visibleDescendantStatusDirty
bit was set; we only clear this bit from collectLayers() (when updating z-order lists), and from styleChanged()
which requires that style changed on the layer itself.

Fix by always calling updateDescendantDependentFlags() from computeCompositingRequirements().

Wasn't able to easily get a reduced testcase.

• rendering/RenderLayerCompositor.cpp:

(WebCore::RenderLayerCompositor::computeCompositingRequirements):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• rendering/RenderLayerCompositor.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-08-21  Simon Fraser  <simon.fraser@apple.com>
+
+        <https://webkit.org/b/116901> ASSERTION FAILED: !m_visibleDescendantStatusDirty on twitter
+
+        Reviewed by Beth Dakin.
+        
+        In order to make decisions about compositing, the m_hasVisibleDescendant bit on RenderLayers
+        needs to be up-to-date when RenderLayerCompositor::computeCompositingRequirements is recursing
+        over the RenderLayer tree.
+        
+        However, was possible for computeCompositingRequirements() to hit a layer whose m_visibleDescendantStatusDirty
+        bit was set; we only clear this bit from collectLayers() (when updating z-order lists), and from styleChanged()
+        which requires that style changed on the layer itself.
+        
+        Fix by always calling updateDescendantDependentFlags() from computeCompositingRequirements().
+
+        Wasn't able to easily get a reduced testcase.
+
+        * rendering/RenderLayerCompositor.cpp:
+        (WebCore::RenderLayerCompositor::computeCompositingRequirements):
+
 2013-08-21  Alex Christensen  <achristensen@apple.com>
 

trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp

@@ -959 +959 @@
 void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* ancestorLayer, RenderLayer* layer, OverlapMap* overlapMap, CompositingState& compositingState, bool& layersChanged, bool& descendantHas3DTransform)
 {
+    layer->updateDescendantDependentFlags();
     layer->updateLayerListsIfNeeded();