[layoutng] async layout part 1: Change the API to support async

third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc

Index: third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
diff --git a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
index 5e3fbe4ea3f4c0ceeab9f5c6990403c3fa625b02..05f612fe4ddd7d63d691f5fa132388e7ee929180 100644
--- a/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
+++ b/third_party/WebKit/Source/core/layout/ng/ng_block_layout_algorithm.cc
@@ -17,15 +17,15 @@ namespace blink {
 NGBlockLayoutAlgorithm::NGBlockLayoutAlgorithm(
     PassRefPtr<const ComputedStyle> style,
     NGBoxIterator box_iterator)
-    : m_style(style), m_boxIterator(box_iterator) {}
+    : style_(style), box_iterator_(box_iterator) {}
 
-NGFragment* NGBlockLayoutAlgorithm::layout(
-    const NGConstraintSpace* constraint_space) {
+bool NGBlockLayoutAlgorithm::Layout(const NGConstraintSpace* constraint_space,
+                                    NGFragment** out) {
   LayoutUnit inline_size =
-      computeInlineSizeForFragment(*constraint_space, *m_style);
+      computeInlineSizeForFragment(*constraint_space, *style_);
   // TODO(layout-ng): For quirks mode, should we pass blockSize instead of -1?
   LayoutUnit block_size =
-      computeBlockSizeForFragment(*constraint_space, *m_style, LayoutUnit(-1));
+      computeBlockSizeForFragment(*constraint_space, *style_, LayoutUnit(-1));
   NGConstraintSpace* constraint_space_for_children = new NGConstraintSpace(
       *constraint_space, NGLogicalSize(inline_size, block_size));
 
@@ -33,10 +33,13 @@ NGFragment* NGBlockLayoutAlgorithm::layout(
   builder.SetInlineSize(inline_size).SetBlockSize(block_size);
 
   LayoutUnit content_size;
-  for (NGBox box : m_boxIterator) {
+  for (NGBox box : box_iterator_) {
     NGBoxStrut child_margins =
         computeMargins(*constraint_space_for_children, *box.style());
-    NGFragment* fragment = box.layout(constraint_space_for_children);
+    NGFragment* fragment;
+    // TODO(layout-ng): Actually make this async
+    while (!box.Layout(constraint_space_for_children, &fragment))
+      ;
     // TODO(layout-ng): Support auto margins
     fragment->SetOffset(child_margins.inline_start,
                         content_size + child_margins.block_start);
@@ -47,14 +50,15 @@ NGFragment* NGBlockLayoutAlgorithm::layout(
 
   // Recompute the block-axis size now that we know our content size.
   block_size =
-      computeBlockSizeForFragment(*constraint_space, *m_style, content_size);
+      computeBlockSizeForFragment(*constraint_space, *style_, content_size);
 
   // TODO(layout-ng): Compute correct inline overflow (block overflow should be
   // correct)
   builder.SetBlockSize(block_size)
       .SetInlineOverflow(inline_size)
       .SetBlockOverflow(content_size);
-  return builder.ToFragment();
+  *out = builder.ToFragment();
+  return true;
 }
 
 }  // namespace blink