Only notify the flowthread about style changes on actual descendants.

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 600d9b8d40123ecc948d3ef9fb1d0242c5b25479..f668620b095015648d489dd76352b72f812f59c8 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -1746,7 +1746,8 @@ void LayoutObject::setStyle(PassRefPtr<ComputedStyle> style)
     diff = adjustStyleDifference(diff);
 
     if (m_style) {
-        if (LayoutFlowThread* flowThread = flowThreadContainingBlock())
+        LayoutFlowThread* flowThread = flowThreadContainingBlock();
+        if (flowThread && flowThread != this)
             flowThread->flowThreadDescendantStyleWillChange(this, diff, *style);
     }
     styleWillChange(diff, *style);
@@ -1766,7 +1767,8 @@ void LayoutObject::setStyle(PassRefPtr<ComputedStyle> style)
 
     styleDidChange(diff, oldStyle.get());
     if (oldStyle.get()) {
-        if (LayoutFlowThread* flowThread = flowThreadContainingBlock())
+        LayoutFlowThread* flowThread = flowThreadContainingBlock();
+        if (flowThread && flowThread != this)
             flowThread->flowThreadDescendantStyleDidChange(this, diff, *oldStyle.get());
     }