Avoid repeated headers correctly in nested paginated tables

We need to keep the accumulated offset around when laying out nested
tables, previously we were resetting it before getting to the nested
tables.

Bug: 759195
Change-Id: I1d87284756e0cb5074c2de0bc4b4f214a708a9ef
Reviewed-on: https://chromium-review.googlesource.com/653279
Commit-Queue: Robert Hogan <[email protected]>
Reviewed-by: Morten Stenshorne <[email protected]>
Cr-Commit-Position: refs/heads/master@{#502058}
diff --git a/third_party/WebKit/LayoutTests/fragmentation/nested-repeating-thead-3-expected.html b/third_party/WebKit/LayoutTests/fragmentation/nested-repeating-thead-3-expected.html
new file mode 100644
index 0000000..68242748
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/fragmentation/nested-repeating-thead-3-expected.html
@@ -0,0 +1,80 @@
+<!DOCTYPE html>
+<style>
+.header {
+  line-height: 40px;
+}
+tr {
+  break-inside: avoid;
+}
+</style>
+<div style="columns:3; column-fill: auto; height:501px; width: 600px; background-color: yellow;">
+  <table cellpadding=0 cellspacing=0>
+    <tr>
+      <td>
+        <div class="header">
+          HEADER<br>HEADER
+        </div>
+      </td>
+    </tr>
+    <tr><td><div style="height: 399px; width: 1px;"></div></td></tr>
+    <tr>
+      <td>
+        <div class="header">
+          HEADER<br>HEADER
+        </div>
+      </td>
+    </tr>
+    <tr><td><div style="height: 399px; width: 1px;"></div></td></tr>
+    <tr>
+      <td>
+        <div class="header">
+          HEADER<br>HEADER
+        </div>
+      </td>
+    </tr>
+    <tr>
+      <td>
+        <div>Text</div>
+        <div>Text</div>
+        <div>Text</div>
+        <table cellpadding="0" cellspacing="0" style="line-height: 20px; width: 200px;">
+          <tr>
+            <td style="width:64px"><strong>Col 1</strong></td>
+            <td><strong>Col 2</strong></td>
+            <td><strong>Col 3</strong></td>
+            <td><strong>Col 4</strong></td>
+            <td><strong>Col 5</strong></td>
+          </tr>
+          <tr>
+            <td style="height:40px">0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+          </tr>
+          <tr>
+            <td style="height:40px">0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+          </tr>
+          <tr>
+            <td style="height:40px">0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+          </tr>
+          <tr>
+            <td style="height:40px">0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+            <td>0</td>
+          </tr>
+        </table>
+      </td>
+    </tr>
+  </table>
+</div>