Make leading OOF objects to be handled by block layout in LayoutNG

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 9fd14255efb568cc83fcfc7da64129b8aba15919..3e9abd5d671ba8aaeedaf0b269388036334bdd4c 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBlockFlow.cpp
@@ -2984,8 +2984,30 @@ void LayoutBlockFlow::AddChild(LayoutObject* new_child,
   // children as blocks.
   // So, if our children are currently inline and a block child has to be
   // inserted, we move all our inline children into anonymous block boxes.
-  bool child_is_block_level =
-      !new_child->IsInline() && !new_child->IsFloatingOrOutOfFlowPositioned();
+  bool child_is_block_level = !new_child->IsInline();
+
+  // ** LayoutNG **
+  // We want to use the block layout for out of flow positioned
+  // objects when they go in front of inline blocks or if they are just
+  // standalone objects.
+  // Example 1:
+  //   <div id="zero"><div id="oof"></div></div>
+  //   Legacy Layout: #oof is in inline context.
+  //   LayoutNG: #oof is in block context.
+  //
+  // Example 2:
+  //   <div id=container><oof></oof>Hello!</div>
+  //   Legacy Layout: oof is in inline context.
+  //   LayoutNG: oof is in block context.
+  //
+  // Example 3:
+  //   <div id=container>Hello!<oof></oof></div>
+  //   Legacy Layout: oof is in inline context.
+  //   LayoutNG: oof is in inline context.

[ikilpatrick, 2017/04/27 20:34:23]

did we want the end children in the inline context? (also this does that?)

+  bool layout_ng_enabled = RuntimeEnabledFeatures::layoutNGEnabled();
+  if (new_child->IsFloatingOrOutOfFlowPositioned())
+    child_is_block_level = layout_ng_enabled && !FirstChild();
+
   if (ChildrenInline()) {
     if (child_is_block_level) {
       // Wrap the inline content in anonymous blocks, to allow for the new block