Actually paint squashed layers when printing.

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index 7e711c8b1a2d9d769e85d0c1db7af10eb3da6204..c6f40ab338050b1b37d2e4783d112ef65821ec1b 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -1575,7 +1575,8 @@ void RenderLayer::paint(GraphicsContext* context, const LayoutRect& damageRect,
     OverlapTestRequestMap overlapTestRequests;
 
     LayerPaintingInfo paintingInfo(this, enclosingIntRect(damageRect), paintBehavior, LayoutSize(), paintingRoot, &overlapTestRequests);
-    paintLayer(context, paintingInfo, paintFlags);
+    if (shouldPaintLayerInSoftwareMode(context, paintingInfo, paintFlags))
+        paintLayer(context, paintingInfo, paintFlags);
 
     OverlapTestRequestMap::iterator end = overlapTestRequests.end();
     for (OverlapTestRequestMap::iterator it = overlapTestRequests.begin(); it != end; ++it)
@@ -1693,17 +1694,13 @@ void RenderLayer::paintLayer(GraphicsContext* context, const LayerPaintingInfo&
     // https://code.google.com/p/chromium/issues/detail?id=343772
     DisableCompositingQueryAsserts disabler;
 
-    if (compositingState() != NotComposited && compositingState() != PaintsIntoGroupedBacking) {
-        // The updatingControlTints() painting pass goes through compositing layers,
-        // but we need to ensure that we don't cache clip rects computed with the wrong root in this case.
+    if (compositingState() != NotComposited) {
         if (context->updatingControlTints() || (paintingInfo.paintBehavior & PaintBehaviorFlattenCompositingLayers)) {
+            // The updatingControlTints() painting pass goes through compositing layers,
+            // but we need to ensure that we don't cache clip rects computed with the wrong root in this case.
+            // FIXME: ok, but what about PaintBehaviorFlattenCompositingLayers? That's for printing.
+            // FIXME: why isn't the code here global, as opposed to being set on each paintLayer() call?
             paintFlags |= PaintLayerUncachedClipRects;
-        } else if (!compositedLayerMapping()->paintsIntoCompositedAncestor()
-            && !shouldDoSoftwarePaint(this, paintFlags & PaintLayerPaintingReflection)
-            && !paintForFixedRootBackground(this, paintFlags)) {
-            // If this RenderLayer should paint into its own backing, that will be done via CompositedLayerMapping::paintContents()
-            // and CompositedLayerMapping::doPaintTask().
-            return;
         }
     } else if (viewportConstrainedNotCompositedReason() == NotCompositedForBoundsOutOfView) {
         // Don't paint out-of-view viewport constrained layers (when doing prepainting) because they will never be visible
@@ -2033,6 +2030,17 @@ void RenderLayer::paintLayerByApplyingTransform(GraphicsContext* context, const
     paintLayerContentsAndReflection(context, transformedPaintingInfo, paintFlags);
 }
 
+bool RenderLayer::shouldPaintLayerInSoftwareMode(GraphicsContext* context, const LayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
+{
+    bool retval =  (compositingState() == NotComposited

[ojan, 2014/07/18 21:27:31]

Nit: no need for the local bool

[chrishtr, 2014/07/18 21:40:21]

Done.

+        || compositingState() == HasOwnBackingButPaintsIntoAncestor
+        || context->updatingControlTints()
+        || (paintingInfo.paintBehavior & PaintBehaviorFlattenCompositingLayers)
+        || shouldDoSoftwarePaint(this, paintFlags & PaintLayerPaintingReflection)

[ojan, 2014/07/18 21:27:31]

This method is confusing now that we have shouldPaintLayerInSoftwareMode. It's
only called here and it's a one-liner. Lets just inline it.

[chrishtr, 2014/07/18 21:40:21]

Done.

+        || paintForFixedRootBackground(this, paintFlags));
+    return retval;
+}
+
 void RenderLayer::paintChildren(unsigned childrenToVisit, GraphicsContext* context, const LayerPaintingInfo& paintingInfo, PaintLayerFlags paintFlags)
 {
     if (!hasSelfPaintingLayerDescendant())
@@ -2045,9 +2053,9 @@ void RenderLayer::paintChildren(unsigned childrenToVisit, GraphicsContext* conte
     RenderLayerStackingNodeIterator iterator(*m_stackingNode, childrenToVisit);
     while (RenderLayerStackingNode* child = iterator.next()) {
         RenderLayer* childLayer = child->layer();
-
-        // Squashed RenderLayers should not paint into their ancestor.
-        if (childLayer->compositingState() == PaintsIntoGroupedBacking)
+        // If this RenderLayer should paint into its own backing or a grouped backing, that will be done via CompositedLayerMapping::paintContents()
+        // and CompositedLayerMapping::doPaintTask().
+        if (!childLayer->shouldPaintLayerInSoftwareMode(context, paintingInfo, paintFlags))
             continue;
 
         if (!childLayer->isPaginated())