Fix regression in page_cycler_v2.tough_layout_cases

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 b0e66841315b3cea38a413ce8e4550d05a91175b..d09bfd46d03a16484f774bccc03d8788232e20d6 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -691,7 +691,6 @@ void LayoutBlockFlow::MarkDescendantsWithFloatsForLayoutIfNeeded(
     // mark it for layout.
     LayoutUnit lowest_float =
         std::max(previous_float_logical_bottom, LowestFloatLogicalBottom());
-    lowest_float = std::max(lowest_float, child.LowestFloatLogicalBottom());
     if (lowest_float > new_logical_top)
       mark_descendants_with_floats = true;
   }
@@ -3717,6 +3716,7 @@ LayoutUnit LayoutBlockFlow::PositionAndLayoutFloat(
     }
   }
 
+  LayoutUnit old_logical_top = child.LogicalTop();
   if (child.NeedsLayout()) {
     if (is_paginated) {
       // Before we can lay out the float, we need to estimate a position for
@@ -3766,6 +3766,17 @@ LayoutUnit LayoutBlockFlow::PositionAndLayoutFloat(
   MarkChildForPaginationRelayoutIfNeeded(child, layout_scope);
   child.LayoutIfNeeded();
 
+  // If negative margin pushes the child completely out of its old position
+  // mark for layout siblings that may have it in its float lists.
+  if (child.LogicalBottom() <= old_logical_top) {
+    LayoutObject* next = child.NextSibling();
+    if (next && next->IsLayoutBlockFlow()) {
+      LayoutBlockFlow* nextBlock = ToLayoutBlockFlow(next);
+      if (!nextBlock->AvoidsFloats() || nextBlock->ShrinkToAvoidFloats())
+        nextBlock->MarkAllDescendantsWithFloatsForLayout();
+    }
+  }
+
   if (is_paginated) {
     PaginatedContentWasLaidOut(child.LogicalBottom());