Invalidate objects when their content box changes dimensions.

third_party/WebKit/Source/core/layout/LayoutBox.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.cpp b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
index 382501f6a7694e0a02dc01d7e081da30305af60f..e06de06fba5997b9ae7005f3873e12617909594d 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -3830,6 +3830,13 @@ PaintInvalidationReason LayoutBox::getPaintInvalidationReason(const LayoutBoxMod
         && hasLayer() && layer()->transform() && !layer()->transform()->isIdentityOrTranslation())
         return PaintInvalidationBoundsChange;
 
+    if (style()->backgroundLayers().thisOrNextLayersUseContentBox() || style()->maskLayers().thisOrNextLayersUseContentBox() || style()->boxSizing() == BoxSizingBorderBox) {
+        LayoutRect oldContentBoxRect = m_rareData ? m_rareData->m_previousContentBoxRect : LayoutRect();
+        LayoutRect newContentBoxRect = contentBoxRect();
+        if (oldContentBoxRect != newContentBoxRect)
+            return PaintInvalidationContentBoxChange;
+    }
+
     if (!style()->hasBackground() && !style()->hasBoxDecorations()) {
         // We could let incremental invalidation cover non-composited scrollbars, but just
         // do a full invalidation because incremental invalidation will go away with slimming paint.
@@ -3838,13 +3845,6 @@ PaintInvalidationReason LayoutBox::getPaintInvalidationReason(const LayoutBoxMod
         return invalidationReason;
     }
 
-    if (style()->backgroundLayers().thisOrNextLayersUseContentBox() || style()->maskLayers().thisOrNextLayersUseContentBox()) {
-        LayoutRect oldContentBoxRect = m_rareData ? m_rareData->m_previousContentBoxRect : LayoutRect();
-        LayoutRect newContentBoxRect = contentBoxRect();
-        if (oldContentBoxRect != newContentBoxRect)
-            return PaintInvalidationContentBoxChange;
-    }
-
     if (style()->backgroundLayers().thisOrNextLayersHaveLocalAttachment()) {
         LayoutRect oldLayoutOverflowRect = m_rareData ? m_rareData->m_previousLayoutOverflowRect : LayoutRect();
         LayoutRect newLayoutOverflowRect = layoutOverflowRect();
@@ -4519,6 +4519,10 @@ bool LayoutBox::needToSavePreviousBoxSizes()
     if (paintInvalidationSize.isEmpty())
         return false;
 
+    // If we use border-box sizing we need to track changes in the size of the content box.
+    if (style()->boxSizing() == BoxSizingBorderBox)
+        return true;
+
     // We need the old box sizes only when the box has background, decorations, or masks.
     // Main LayoutView paints base background, thus interested in box size.
     if (!isLayoutView() && !style()->hasBackground() && !style()->hasBoxDecorations() && !style()->hasMask())