Update hasVisibleContent() to include visibility of non-self-painting layers.

Source/core/paint/DeprecatedPaintLayer.cpp

Index: Source/core/paint/DeprecatedPaintLayer.cpp
diff --git a/Source/core/paint/DeprecatedPaintLayer.cpp b/Source/core/paint/DeprecatedPaintLayer.cpp
index 35816c7fce8fc8f7916048454bae7897b8e2df9d..02ad94396689f533436f40f847a807018973cfed 100644
--- a/Source/core/paint/DeprecatedPaintLayer.cpp
+++ b/Source/core/paint/DeprecatedPaintLayer.cpp
@@ -594,6 +594,8 @@ void DeprecatedPaintLayer::dirtyVisibleContentStatus()
     m_visibleContentStatusDirty = true;
     if (parent())
         parent()->dirtyAncestorChainVisibleDescendantStatus();
+    if (!isSelfPaintingLayer())
+        parent()->dirtyVisibleContentStatus();

[chrishtr, 2015/06/25 17:26:50]

compositing/contents-opaque/visibility-hidden.html exercises this code, because
the <nav> element in that test is a non-self-painting layer.

 }
 
 void DeprecatedPaintLayer::potentiallyDirtyVisibleContentStatus(EVisibility visibility)
@@ -664,12 +666,12 @@ void DeprecatedPaintLayer::updateDescendantDependentFlags()
             m_hasVisibleContent = false;
             LayoutObject* r = layoutObject()->slowFirstChild();
             while (r) {
-                if (r->style()->visibility() == VISIBLE && !r->hasLayer()) {
+                if (r->style()->visibility() == VISIBLE && (!r->hasLayer() || !r->enclosingLayer()->isSelfPaintingLayer())) {
                     m_hasVisibleContent = true;
                     break;
                 }
                 LayoutObject* layoutObjectFirstChild = r->slowFirstChild();
-                if (layoutObjectFirstChild && !r->hasLayer()) {
+                if (layoutObjectFirstChild && (!r->hasLayer() || !r->enclosingLayer()->isSelfPaintingLayer())) {
                     r = layoutObjectFirstChild;
                 } else if (r->nextSibling()) {
                     r = r->nextSibling();
@@ -1150,6 +1152,10 @@ void DeprecatedPaintLayer::addChild(DeprecatedPaintLayer* child, DeprecatedPaint
         child->stackingNode()->dirtyStackingContextZOrderLists();
     }
 
+    // Non-self-painting children paint into this layer, so the visible contents status of this layer is affected.
+    if (!child->isSelfPaintingLayer())
+        dirtyVisibleContentStatus();
+
     dirtyAncestorChainVisibleDescendantStatus();
     dirtyAncestorChainHasSelfPaintingLayerDescendantStatus();