Refine the criteria for ScrollAnchor-disabling properties

third_party/WebKit/Source/core/style/ComputedStyle.cpp

Index: third_party/WebKit/Source/core/style/ComputedStyle.cpp
diff --git a/third_party/WebKit/Source/core/style/ComputedStyle.cpp b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
index 08db13def869a7d84a2ab03df1efeb663de58b75..935bc431515c0bc859e42937d60581a679ff7a8a 100644
--- a/third_party/WebKit/Source/core/style/ComputedStyle.cpp
+++ b/third_party/WebKit/Source/core/style/ComputedStyle.cpp
@@ -598,9 +598,7 @@ StyleDifference ComputedStyle::visualInvalidationDiff(
 
   updatePropertySpecificDifferences(other, diff);
 
-  // TODO(skobes): Refine the criteria for ScrollAnchor-disabling properties.
-  // Some things set needsLayout but shouldn't disable scroll anchoring.
-  if (diff.needsLayout() || diff.transformChanged())
+  if (scrollAnchorDisablingPropertyChanged(other, diff))
     diff.setScrollAnchorDisablingPropertyChanged();
 
   // Cursors are not checked, since they will be set appropriately in response
@@ -614,6 +612,35 @@ StyleDifference ComputedStyle::visualInvalidationDiff(
   return diff;
 }
 
+bool ComputedStyle::scrollAnchorDisablingPropertyChanged(
+    const ComputedStyle& other,
+    StyleDifference& diff) const {
+  if (m_nonInheritedData.m_position != other.m_nonInheritedData.m_position)
+    return true;
+
+  if (m_box.get() != other.m_box.get()) {
+    if (m_box->width() != other.m_box->width() ||
+        m_box->minWidth() != other.m_box->minWidth() ||
+        m_box->maxWidth() != other.m_box->maxWidth() ||
+        m_box->height() != other.m_box->height() ||
+        m_box->minHeight() != other.m_box->minHeight() ||
+        m_box->maxHeight() != other.m_box->maxHeight())
+      return true;
+  }
+
+  if (m_surround.get() != other.m_surround.get()) {
+    if (m_surround->margin != other.m_surround->margin ||
+        m_surround->offset != other.m_surround->offset ||
+        m_surround->padding != other.m_surround->padding)
+      return true;
+  }
+
+  if (diff.transformChanged())
+    return true;
+
+  return false;
+}
+
 bool ComputedStyle::diffNeedsFullLayoutAndPaintInvalidation(
     const ComputedStyle& other) const {
   // FIXME: Not all cases in this method need both full layout and paint