Only the first layout pass needs to go deep when pagination state changes.

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

Index: third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
index 90580735abd81b1b7186e0d19831340fb5888269..1514c642f90d7823cb023e6b5ee137a82bf5982e 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -408,22 +408,23 @@ void LayoutBlockFlow::layoutBlock(bool relayoutChildren) {
   relayoutChildren |= logicalWidthChanged;
 
   TextAutosizer::LayoutScope textAutosizerLayoutScope(this, &layoutScope);
-  LayoutState state(*this, logicalWidthChanged);
-
-  if (m_paginationStateChanged) {
-    // We now need a deep layout to clean up struts after pagination, if we
-    // just ceased to be paginated, or, if we just became paginated on the
-    // other hand, we now need the deep layout, to insert pagination struts.
-    m_paginationStateChanged = false;
-    state.setPaginationStateChanged();
-  }
 
+  bool paginationStateChanged = m_paginationStateChanged;
   bool preferredLogicalWidthsWereDirty = preferredLogicalWidthsDirty();
 
   // Multiple passes might be required for column based layout.
   // The number of passes could be as high as the number of columns.
   LayoutMultiColumnFlowThread* flowThread = multiColumnFlowThread();
   do {
+    LayoutState state(*this, logicalWidthChanged);
+    if (m_paginationStateChanged) {
+      // We now need a deep layout to clean up struts after pagination, if we
+      // just ceased to be paginated, or, if we just became paginated on the
+      // other hand, we now need the deep layout, to insert pagination struts.
+      m_paginationStateChanged = false;
+      state.setPaginationStateChanged();
+    }
+
     layoutChildren(relayoutChildren, layoutScope);
 
     if (!preferredLogicalWidthsWereDirty && preferredLogicalWidthsDirty()) {
@@ -448,6 +449,13 @@ void LayoutBlockFlow::layoutBlock(bool relayoutChildren) {
     break;
   } while (true);
 
+  LayoutState state(*this, logicalWidthChanged);
+  if (paginationStateChanged) {
+    // We still haven't laid out positioned descendants, and we need to perform
+    // a deep layout on those too if pagination state changed.
+    state.setPaginationStateChanged();
+  }
+
   // Remember the automatic logical height we got from laying out the children.
   LayoutUnit unconstrainedHeight = logicalHeight();
   LayoutUnit unconstrainedClientAfterEdge = clientLogicalBottom();