Enable position:sticky for <thead> and <tr> elements

third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp

Index: third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp b/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
index e466983bb4cd90ea840b3d69d382738b36287cc1..070df8bd9e04c64cdd66e096df32224cc3273908 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
@@ -340,16 +340,14 @@ static void AdjustStyleForDisplay(ComputedStyle& style,
       style.GetWritingMode() != layout_parent_style.GetWritingMode())
     style.SetDisplay(EDisplay::kInlineBlock);
 
-  // We do not honor position: relative or sticky for table rows, headers, and
-  // footers. This is correct for position: relative in CSS2.1 (and caused a
-  // crash in containingBlock() on some sites) and position: sticky is defined
-  // as following position: relative behavior for table elements. It is
-  // incorrect for CSS3.
+  // We do not honor position: relative for table rows, headers, and footers.
+  // This is correct for CSS2.1 (and honoring it caused a crash in
+  // containingBlock() on some sites). It is incorrect for CSS3.
   if ((style.Display() == EDisplay::kTableHeaderGroup ||
        style.Display() == EDisplay::kTableRowGroup ||
        style.Display() == EDisplay::kTableFooterGroup ||
        style.Display() == EDisplay::kTableRow) &&
-      style.HasInFlowPosition())
+      style.GetPosition() == EPosition::kRelative)
     style.SetPosition(EPosition::kStatic);
 
   // Cannot support position: sticky for table columns and column groups because