Provide a dedicated getter for the offset to a repeatable THEAD.

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

Index: third_party/WebKit/Source/core/layout/LayoutTable.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutTable.cpp b/third_party/WebKit/Source/core/layout/LayoutTable.cpp
index 5d3edd3625fba4fb60f42dfdb100eb2fa9f3efe7..e2527c905d346f31f99990a5529eb4848fe558e2 100644
--- a/third_party/WebKit/Source/core/layout/LayoutTable.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutTable.cpp
@@ -732,16 +732,18 @@ void LayoutTable::layout() {
 
     computeOverflow(clientLogicalBottom());
     updateAfterLayout();
+
+    if (state.pageLogicalHeight()) {
+      LayoutUnit offset = state.pageLogicalOffset(*this, LayoutUnit());
+      m_offsetToFirstRepeatableHeader = offset;
+      setPageLogicalOffset(offset);
+    }
   }
 
   // FIXME: This value isn't the intrinsic content logical height, but we need
   // to update the value as its used by flexbox layout. crbug.com/367324
   setIntrinsicContentLogicalHeight(contentLogicalHeight());
 
-  if (view()->layoutState()->pageLogicalHeight())
-    setPageLogicalOffset(
-        view()->layoutState()->pageLogicalOffset(*this, logicalTop()));
-
   m_columnLogicalWidthChanged = false;
   clearNeedsLayout();
 }