Don't coerce pointers to compositor layer mappings to booleans.

Source/core/rendering/RenderLayerRepainter.cpp

Index: Source/core/rendering/RenderLayerRepainter.cpp
diff --git a/Source/core/rendering/RenderLayerRepainter.cpp b/Source/core/rendering/RenderLayerRepainter.cpp
index 595431fa03737e99e3ad08967d41ad64011efeba..c898f4021751c905b2e8227ab74e0ea2a055cc7d 100644
--- a/Source/core/rendering/RenderLayerRepainter.cpp
+++ b/Source/core/rendering/RenderLayerRepainter.cpp
@@ -135,7 +135,9 @@ void RenderLayerRepainter::repaintIncludingNonCompositingDescendants(RenderLayer
     m_renderer->repaintUsingContainer(repaintContainer, pixelSnappedIntRect(m_renderer->clippedOverflowRectForRepaint(repaintContainer)));
 
     for (RenderLayer* curr = m_renderer->layer()->firstChild(); curr; curr = curr->nextSibling()) {
-        if (!curr->compositedLayerMapping())
+        // FIXME: we also want to paint those layers who have a backing but paint into
+        // our repaint container.
+        if (curr->compositingState() == NotComposited)

[shawnsingh, 2013/11/12 09:55:50]

I don't understand this FIXME... why cant we just write:
  if (curr->compositingState() == NotComposited || curr->compositingState() ==
HasOwnBackingButPaintsIntoAncestor)

which would be equivalent to the previous code, and address your FIXME all at
the same time?

[Ian Vollick, 2013/11/14 04:12:47]

Ah right. We want to paint those layers that paint into our repaint container,
but I was worried that the paints-into-ancestor layers may paint into some other
container (is that impossible? seems quite possible in the world of squashing).
I put the FIXME here so I could add the container comparison code in another
patch.

             curr->repainter().repaintIncludingNonCompositingDescendants(repaintContainer);
     }
 }
@@ -145,7 +147,9 @@ LayoutRect RenderLayerRepainter::repaintRectIncludingNonCompositingDescendants()
     LayoutRect repaintRect = m_repaintRect;
     for (RenderLayer* child = m_renderer->layer()->firstChild(); child; child = child->nextSibling()) {
         // Don't include repaint rects for composited child layers; they will paint themselves and have a different origin.
-        if (child->compositedLayerMapping())
+        // FIXME: we also want to include those layers who have a backing but paint into
+        // our repaint container.
+        if (child->compositingState() != NotComposited)

[shawnsingh, 2013/11/12 09:55:50]

This code doesn't seem to require a FIXME, either?

[Ian Vollick, 2013/11/14 04:12:47]

Same as above.

             continue;
 
         repaintRect.unite(child->repainter().repaintRectIncludingNonCompositingDescendants());
@@ -155,7 +159,7 @@ LayoutRect RenderLayerRepainter::repaintRectIncludingNonCompositingDescendants()
 
 void RenderLayerRepainter::setBackingNeedsRepaint()
 {
-    ASSERT(m_renderer->compositedLayerMapping());
+    ASSERT(m_renderer->hasCompositedLayerMapping());
     m_renderer->compositedLayerMapping()->setContentsNeedDisplay();
 }
 
@@ -163,8 +167,8 @@ void RenderLayerRepainter::setBackingNeedsRepaintInRect(const LayoutRect& r)
 {
     // https://bugs.webkit.org/show_bug.cgi?id=61159 describes an unreproducible crash here,
     // so assert but check that the layer is composited.
-    ASSERT(m_renderer->compositedLayerMapping());
-    if (!m_renderer->compositedLayerMapping()) {
+    ASSERT(m_renderer->hasCompositedLayerMapping());
+    if (!m_renderer->hasCompositedLayerMapping()) {
         // If we're trying to repaint the placeholder document layer, propagate the
         // repaint to the native view system.
         LayoutRect absRect(r);
@@ -212,7 +216,7 @@ void RenderLayerRepainter::setFilterBackendNeedsRepaintingInRect(const LayoutRec
     FloatQuad repaintQuad(rectForRepaint);
     LayoutRect parentLayerRect = m_renderer->localToContainerQuad(repaintQuad, parentLayer->renderer()).enclosingBoundingBox();
 
-    if (parentLayer->compositedLayerMapping()) {
+    if (parentLayer->compositingState() == PaintsIntoOwnBacking) {
         parentLayer->repainter().setBackingNeedsRepaintInRect(parentLayerRect);
         return;
     }