Enforce clearing renderers' paint invalidation state

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index 96e2848c46e42e825ec21e079a0178d379c21fae..0cca4fd54ce0ba50eb562c67a2a018b8ca251997 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -246,6 +246,27 @@ public:
             renderer->assertRendererLaidOut();
     }
 
+    void assertRendererClearedPaintInvalidationState() const
+    {
+        if (paintInvalidationStateIsDirty()) {

[dsinclair, 2014/07/11 20:48:55]

if (!paintInvalidationStateIsDirt())
  return;

[Julien - ping for review, 2014/07/11 20:52:46]

A'right.

+            showRenderTreeForThis();

[dsinclair, 2014/07/11 20:48:55]

Is this included on purpose?

[Julien - ping for review, 2014/07/11 20:52:46]

It is, see assertRendererLaidOut() above. The reason is that it makes debugging
way easier.

+            ASSERT_NOT_REACHED();
+        }
+    }
+
+    void assertSubtreeClearedPaintInvalidationState() const
+    {
+        for (const RenderObject* renderer = this; renderer; renderer = renderer->nextInPreOrder()) {
+            renderer->assertRendererClearedPaintInvalidationState();
+
+            // Currently we skip some SVG containers for performance (see RenderSVGModelObject::invalidateTreeAfterLayout)
+            // so we just skip the underlying subtree. This is not strictly the condition in the previous function but
+            // it makes little sense to cover SVG subtrees if we know they are skipped anyway.
+            if (renderer->isSVGContainer())
+                return;
+        }
+    }
+
 #endif
 
     bool skipInvalidationWhenLaidOutChildren() const;
@@ -1008,10 +1029,10 @@ public:
 
     // layoutDidGetCalled indicates whether this render object was re-laid-out
     // since the last call to setLayoutDidGetCalled(false) on this object.
-    bool layoutDidGetCalled() { return m_bitfields.layoutDidGetCalled(); }
+    bool layoutDidGetCalled() const { return m_bitfields.layoutDidGetCalled(); }
     void setLayoutDidGetCalled(bool b) { m_bitfields.setLayoutDidGetCalled(b); }
 
-    bool mayNeedPaintInvalidation() { return m_bitfields.mayNeedPaintInvalidation(); }
+    bool mayNeedPaintInvalidation() const { return m_bitfields.mayNeedPaintInvalidation(); }
     void setMayNeedPaintInvalidation(bool b)
     {
         m_bitfields.setMayNeedPaintInvalidation(b);
@@ -1026,7 +1047,7 @@ public:
 
     bool shouldCheckForPaintInvalidationAfterLayout()
     {
-        return layoutDidGetCalled() || mayNeedPaintInvalidation();
+        return layoutDidGetCalled() || mayNeedPaintInvalidation() || shouldDoFullPaintInvalidationAfterLayout();
     }
 
     bool supportsLayoutStateCachedOffsets() const { return !hasColumns() && !hasTransform() && !hasReflection() && !style()->isFlippedBlocksWritingMode(); }
@@ -1112,6 +1133,12 @@ private:
 
 #ifndef NDEBUG
     void checkBlockPositionedObjectsNeedLayout();
+
+    bool paintInvalidationStateIsDirty() const
+    {
+        return layoutDidGetCalled() || shouldDoFullPaintInvalidationAfterLayout() || shouldDoFullPaintInvalidationIfSelfPaintingLayer()
+            || onlyNeededPositionedMovementLayout() || neededLayoutBecauseOfChildren() || mayNeedPaintInvalidation();
+    }
 #endif
     const char* invalidationReasonToString(InvalidationReason) const;