No need to reattach legacy/ng layout after style recalc.

We no longer (re-)attach the layout tree from style recalc.

Change-Id: Ia944649b6e12345c23ecbd7e6ea91d8d6aaba94c
Reviewed-on: https://chromium-review.googlesource.com/1190205Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586366}

third_party/blink/renderer/core/dom/document.cc

@@ -2304,10 +2304,7 @@ void Document::UpdateStyle() {
       TRACE_EVENT0("blink,blink_style", "Document::recalcStyle");
       SCOPED_BLINK_UMA_HISTOGRAM_TIMER_HIGHRES("Style.RecalcTime");
       Element* viewport_defining = ViewportDefiningElement();
-      ReattachLegacyLayoutObjectList legacy_layout_objects(*this);
-      legacy_layout_objects.WillRecalcStyle();
       document_element->RecalcStyle(change);
-      legacy_layout_objects.DidRecalcStyle();
       if (viewport_defining != ViewportDefiningElement())
         ViewportDefiningElementDidChange();
     }

third_party/blink/renderer/core/dom/layout_tree_builder.cc

@@ -284,7 +284,7 @@ void ReattachLegacyLayoutObjectList::AddForceLegacyAtBFCAncestor(
 }
 
 bool ReattachLegacyLayoutObjectList::IsCollecting() const {
-  return state_ == State::kCollecting || state_ == State::kRecalcStyle;
+  return state_ == State::kCollecting;
 }
 
 void ReattachLegacyLayoutObjectList::ForceLegacyLayoutIfNeeded() {
@@ -305,26 +305,6 @@ void ReattachLegacyLayoutObjectList::ForceLegacyLayoutIfNeeded() {
   state_ = State::kClosed;
 }
 
-void ReattachLegacyLayoutObjectList::DidRecalcStyle() {
-  const State state = state_;
-  state_ = State::kClosed;
-  if (state == State::kBuildingLegacyLayoutTree)
-    return;
-  DCHECK_EQ(state, State::kRecalcStyle);
-  for (const LayoutObject* block : blocks_)
-    ToElement(*block->GetNode()).LazyReattachIfAttached();
-}
-
-void ReattachLegacyLayoutObjectList::WillRecalcStyle() {
-  // TODO(layout-dev): Once make |RecalcStyle()| not to create layout object,
-  // we don't need to have |WillRecalcStyle()| and |DidRecalcStyle()|.
-  // Note: "first-letter-removed-added.html" creates layout object during
-  // style recalc. See http://crbug.com/847218
-  if (state_ == State::kBuildingLegacyLayoutTree)
-    return;
-  state_ = State::kRecalcStyle;
-}
-
 void ReattachLegacyLayoutObjectList::Trace(blink::Visitor* visitor) {
   visitor->Trace(document_);
 }

third_party/blink/renderer/core/dom/layout_tree_builder.h

@@ -158,9 +158,6 @@ class CORE_EXPORT ReattachLegacyLayoutObjectList final {
   }
   void ForceLegacyLayoutIfNeeded();
 
-  void DidRecalcStyle();
-  void WillRecalcStyle();
-
   void Trace(blink::Visitor*);
 
  private:
@@ -180,8 +177,6 @@ class CORE_EXPORT ReattachLegacyLayoutObjectList final {
     kCollecting,
     // Replaces LayoutNG objects to legacy layout objects.
     kForcingLegacyLayout,
-    // Doing style re-calculation.
-    kRecalcStyle,
   } state_ = State::kInvalid;
 
   DISALLOW_COPY_AND_ASSIGN(ReattachLegacyLayoutObjectList);