Remove outdated FIXME

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index f668620b095015648d489dd76352b72f812f59c8..7e6083f904cb35ce7e046973b7887e9ab5f8c82f 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -1140,7 +1140,7 @@ LayoutRect LayoutObject::computePaintInvalidationRect(const LayoutBoxModelObject
     return clippedOverflowRectForPaintInvalidation(paintInvalidationContainer, paintInvalidationState);
 }
 
-void LayoutObject::invalidatePaintUsingContainer(const LayoutBoxModelObject* paintInvalidationContainer, const LayoutRect& r, PaintInvalidationReason invalidationReason) const
+void LayoutObject::invalidatePaintUsingContainer(const LayoutBoxModelObject& paintInvalidationContainer, const LayoutRect& r, PaintInvalidationReason invalidationReason) const
 {
     ASSERT(gDisablePaintInvalidationStateAsserts || document().lifecycle().state() == DocumentLifecycle::InPaintInvalidation);
 
@@ -1153,19 +1153,19 @@ void LayoutObject::invalidatePaintUsingContainer(const LayoutBoxModelObject* pai
     TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.invalidationTracking"),
         "PaintInvalidationTracking",
         TRACE_EVENT_SCOPE_THREAD,
-        "data", InspectorPaintInvalidationTrackingEvent::data(this, paintInvalidationContainer));
+        "data", InspectorPaintInvalidationTrackingEvent::data(this, &paintInvalidationContainer));

[Julien - ping for review, 2015/05/29 18:19:12]

It seems like we should change this function to use a reference too.

[huayong.xu, 2015/06/01 02:42:39]

Done.

     TRACE_EVENT2(TRACE_DISABLED_BY_DEFAULT("blink.invalidation"), "LayoutObject::invalidatePaintUsingContainer()",
         "object", this->debugName().ascii(),
         "info", jsonObjectForPaintInvalidationInfo(r, paintInvalidationReasonToString(invalidationReason)));
 
-    if (paintInvalidationContainer->isLayoutView()) {
-        toLayoutView(paintInvalidationContainer)->invalidatePaintForRectangle(r, invalidationReason);
+    if (paintInvalidationContainer.isLayoutView()) {
+        toLayoutView(&paintInvalidationContainer)->invalidatePaintForRectangle(r, invalidationReason);
         return;
     }
 
-    if (paintInvalidationContainer->view()->usesCompositing()) {
-        ASSERT(paintInvalidationContainer->isPaintInvalidationContainer());
-        paintInvalidationContainer->setBackingNeedsPaintInvalidationInRect(r, invalidationReason);
+    if (paintInvalidationContainer.view()->usesCompositing()) {
+        ASSERT(paintInvalidationContainer.isPaintInvalidationContainer());
+        paintInvalidationContainer.setBackingNeedsPaintInvalidationInRect(r, invalidationReason);
     }
 }
 
@@ -1230,10 +1230,10 @@ const LayoutBoxModelObject* LayoutObject::invalidatePaintRectangleInternal(const
 
     LayoutRect dirtyRect(r);
 
-    const LayoutBoxModelObject* paintInvalidationContainer = containerForPaintInvalidation();
-    DeprecatedPaintLayer::mapRectToPaintInvalidationBacking(this, paintInvalidationContainer, dirtyRect);
+    const LayoutBoxModelObject& paintInvalidationContainer = *containerForPaintInvalidation();

[Julien - ping for review, 2015/05/29 18:19:12]

I think we should still check that the returned pointer is not NULL (it should
never be NULL because we check for isRooted() above).

The best would be to add a new containerForPaintInvalidationOnRootedTree that
does the following:
- ASSERT(isRooted());
- Call containerForPaintInvalidation()
- Check that the returned result is not NULL.
- Return a reference to it.

That would ensure that we catch bad assumptions in the code. Hopefully we could
convert every callers to containerForPaintInvalidationOnRootedTree and fold it
into containerForPaintInvalidation but that's a stretch goal.

[huayong.xu, 2015/06/01 02:42:39]

Done.

+    DeprecatedPaintLayer::mapRectToPaintInvalidationBacking(this, &paintInvalidationContainer, dirtyRect);
     invalidatePaintUsingContainer(paintInvalidationContainer, dirtyRect, PaintInvalidationRectangle);
-    return paintInvalidationContainer;
+    return &paintInvalidationContainer;
 }
 
 void LayoutObject::invalidatePaintRectangle(const LayoutRect& r) const
@@ -1429,23 +1429,23 @@ void LayoutObject::incrementallyInvalidatePaint(const LayoutBoxModelObject& pain
 
     LayoutUnit deltaRight = newBounds.maxX() - oldBounds.maxX();
     if (deltaRight > 0)
-        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), PaintInvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(oldBounds.maxX(), newBounds.y(), deltaRight, newBounds.height()), PaintInvalidationIncremental);
     else if (deltaRight < 0)
-        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), PaintInvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(newBounds.maxX(), oldBounds.y(), -deltaRight, oldBounds.height()), PaintInvalidationIncremental);
 
     LayoutUnit deltaBottom = newBounds.maxY() - oldBounds.maxY();
     if (deltaBottom > 0)
-        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), PaintInvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(newBounds.x(), oldBounds.maxY(), newBounds.width(), deltaBottom), PaintInvalidationIncremental);
     else if (deltaBottom < 0)
-        invalidatePaintUsingContainer(&paintInvalidationContainer, LayoutRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), PaintInvalidationIncremental);
+        invalidatePaintUsingContainer(paintInvalidationContainer, LayoutRect(oldBounds.x(), newBounds.maxY(), oldBounds.width(), -deltaBottom), PaintInvalidationIncremental);
 }
 
 void LayoutObject::fullyInvalidatePaint(const LayoutBoxModelObject& paintInvalidationContainer, PaintInvalidationReason invalidationReason, const LayoutRect& oldBounds, const LayoutRect& newBounds)
 {
     // Otherwise do full paint invalidation.
-    invalidatePaintUsingContainer(&paintInvalidationContainer, oldBounds, invalidationReason);
+    invalidatePaintUsingContainer(paintInvalidationContainer, oldBounds, invalidationReason);
     if (newBounds != oldBounds)
-        invalidatePaintUsingContainer(&paintInvalidationContainer, newBounds, invalidationReason);
+        invalidatePaintUsingContainer(paintInvalidationContainer, newBounds, invalidationReason);
 }
 
 void LayoutObject::invalidatePaintForOverflow()
@@ -3253,14 +3253,14 @@ DisablePaintInvalidationStateAsserts::DisablePaintInvalidationStateAsserts()
 // Since we're only painting non-composited layers, we know that they all share the same paintInvalidationContainer.
 void LayoutObject::invalidatePaintIncludingNonCompositingDescendants()
 {
-    invalidatePaintIncludingNonCompositingDescendantsInternal(containerForPaintInvalidation());
+    invalidatePaintIncludingNonCompositingDescendantsInternal(*containerForPaintInvalidation());
 }
 
-void LayoutObject::invalidatePaintIncludingNonCompositingDescendantsInternal(const LayoutBoxModelObject* paintInvalidationContainer)
+void LayoutObject::invalidatePaintIncludingNonCompositingDescendantsInternal(const LayoutBoxModelObject& paintInvalidationContainer)
 {
     invalidatePaintUsingContainer(paintInvalidationContainer, previousPaintInvalidationRect(), PaintInvalidationLayer);
     if (RuntimeEnabledFeatures::slimmingPaintEnabled())
-        invalidateDisplayItemClients(*paintInvalidationContainer);
+        invalidateDisplayItemClients(paintInvalidationContainer);
 
     for (LayoutObject* child = slowFirstChild(); child; child = child->nextSibling()) {
         if (!child->isPaintInvalidationContainer())