Move RebuildLayoutTree/RecalcStyle to StyleEngine.

In preparation for starting those operations from a different root node
than the document root, make them separate methods on StyleEngine.

Bug: 868810
Change-Id: Ic3c1308835aef9a4e7887822ad7744ae76a7dcbd
Reviewed-on: https://chromium-review.googlesource.com/1206910Reviewed-by: Anders Ruud <andruud@chromium.org>
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#589476}

third_party/blink/renderer/core/css/style_engine.cc

@@ -1545,6 +1545,21 @@ DocumentStyleEnvironmentVariables& StyleEngine::EnsureEnvironmentVariables() {
   return *environment_variables_.get();
 }
 
+void StyleEngine::RecalcStyle(StyleRecalcChange change) {
+  DCHECK(GetDocument().documentElement());
+  DCHECK(GetDocument().ChildNeedsStyleRecalc() || change == kForce);
+
+  GetDocument().documentElement()->RecalcStyle(change);
+}
+
+void StyleEngine::RebuildLayoutTree() {
+  DCHECK(GetDocument().documentElement());
+  DCHECK(GetDocument().ChildNeedsReattachLayoutTree());
+
+  WhitespaceAttacher whitespace_attacher;
+  GetDocument().documentElement()->RebuildLayoutTree(whitespace_attacher);
+}
+
 void StyleEngine::Trace(blink::Visitor* visitor) {
   visitor->Trace(document_);
   visitor->Trace(injected_user_style_sheets_);

third_party/blink/renderer/core/css/style_engine.h

@@ -319,6 +319,9 @@ class CORE_EXPORT StyleEngine final
 
   DocumentStyleEnvironmentVariables& EnsureEnvironmentVariables();
 
+  void RecalcStyle(StyleRecalcChange change);
+  void RebuildLayoutTree();
+
   void Trace(blink::Visitor*) override;
   const char* NameInHeapSnapshot() const override { return "StyleEngine"; }
 

third_party/blink/renderer/core/css/style_engine_test.cc

@@ -848,14 +848,12 @@ TEST_F(StyleEngineTest, HasViewportDependentMediaQueries) {
     GetDocument().View()->UpdateAllLifecyclePhases();
   }
 
-  EXPECT_TRUE(
-      GetDocument().GetStyleEngine().HasViewportDependentMediaQueries());
+  EXPECT_TRUE(GetStyleEngine().HasViewportDependentMediaQueries());
 
   GetDocument().body()->RemoveChild(style_element);
   GetDocument().View()->UpdateAllLifecyclePhases();
 
-  EXPECT_FALSE(
-      GetDocument().GetStyleEngine().HasViewportDependentMediaQueries());
+  EXPECT_FALSE(GetStyleEngine().HasViewportDependentMediaQueries());
 }
 
 TEST_F(StyleEngineTest, StyleMediaAttributeStyleChange) {
@@ -1482,7 +1480,7 @@ TEST_F(StyleEngineTest, RejectSelectorForPseudoElement) {
   )HTML");
   GetDocument().View()->UpdateAllLifecyclePhases();
 
-  StyleEngine& engine = GetDocument().GetStyleEngine();
+  StyleEngine& engine = GetStyleEngine();
   engine.SetStatsEnabled(true);
 
   StyleResolverStats* stats = engine.Stats();
@@ -1493,7 +1491,7 @@ TEST_F(StyleEngineTest, RejectSelectorForPseudoElement) {
   div->SetInlineStyleProperty(CSSPropertyColor, "green");
 
   GetDocument().Lifecycle().AdvanceTo(DocumentLifecycle::kInStyleRecalc);
-  GetDocument().documentElement()->RecalcStyle(kNoChange);
+  GetStyleEngine().RecalcStyle(kNoChange);
 
   // Should fast reject ".not-in-filter div::before {}" for both the div and its
   // ::before pseudo element.
@@ -1514,35 +1512,35 @@ TEST_F(StyleEngineTest, MarkForWhitespaceReattachment) {
   GetDocument().View()->UpdateAllLifecyclePhases();
 
   d1->firstChild()->remove();
-  EXPECT_TRUE(GetDocument().GetStyleEngine().NeedsWhitespaceReattachment(d1));
+  EXPECT_TRUE(GetStyleEngine().NeedsWhitespaceReattachment(d1));
   EXPECT_FALSE(GetDocument().ChildNeedsStyleInvalidation());
   EXPECT_FALSE(GetDocument().ChildNeedsStyleRecalc());
   EXPECT_FALSE(GetDocument().ChildNeedsReattachLayoutTree());
 
-  GetDocument().GetStyleEngine().MarkForWhitespaceReattachment();
+  GetStyleEngine().MarkForWhitespaceReattachment();
   EXPECT_FALSE(GetDocument().ChildNeedsReattachLayoutTree());
 
   GetDocument().View()->UpdateAllLifecyclePhases();
 
   d2->firstChild()->remove();
   d2->firstChild()->remove();
-  EXPECT_TRUE(GetDocument().GetStyleEngine().NeedsWhitespaceReattachment(d2));
+  EXPECT_TRUE(GetStyleEngine().NeedsWhitespaceReattachment(d2));
   EXPECT_FALSE(GetDocument().ChildNeedsStyleInvalidation());
   EXPECT_FALSE(GetDocument().ChildNeedsStyleRecalc());
   EXPECT_FALSE(GetDocument().ChildNeedsReattachLayoutTree());
 
-  GetDocument().GetStyleEngine().MarkForWhitespaceReattachment();
+  GetStyleEngine().MarkForWhitespaceReattachment();
   EXPECT_FALSE(GetDocument().ChildNeedsReattachLayoutTree());
 
   GetDocument().View()->UpdateAllLifecyclePhases();
 
   d3->firstChild()->remove();
-  EXPECT_TRUE(GetDocument().GetStyleEngine().NeedsWhitespaceReattachment(d3));
+  EXPECT_TRUE(GetStyleEngine().NeedsWhitespaceReattachment(d3));
   EXPECT_FALSE(GetDocument().ChildNeedsStyleInvalidation());
   EXPECT_FALSE(GetDocument().ChildNeedsStyleRecalc());
   EXPECT_FALSE(GetDocument().ChildNeedsReattachLayoutTree());
 
-  GetDocument().GetStyleEngine().MarkForWhitespaceReattachment();
+  GetStyleEngine().MarkForWhitespaceReattachment();
   EXPECT_TRUE(GetDocument().ChildNeedsReattachLayoutTree());
 }
 

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

@@ -2304,7 +2304,7 @@ void Document::UpdateStyle() {
       TRACE_EVENT0("blink,blink_style", "Document::recalcStyle");
       SCOPED_BLINK_UMA_HISTOGRAM_TIMER_HIGHRES("Style.RecalcTime");
       Element* viewport_defining = ViewportDefiningElement();
-      document_element->RecalcStyle(change);
+      GetStyleEngine().RecalcStyle(change);
       if (viewport_defining != ViewportDefiningElement())
         ViewportDefiningElementDidChange();
     }
@@ -2315,8 +2315,7 @@ void Document::UpdateStyle() {
       TRACE_EVENT0("blink,blink_style", "Document::rebuildLayoutTree");
       SCOPED_BLINK_UMA_HISTOGRAM_TIMER_HIGHRES("Style.RebuildLayoutTreeTime");
       ReattachLegacyLayoutObjectList legacy_layout_objects(*this);
-      WhitespaceAttacher whitespace_attacher;
-      document_element->RebuildLayoutTree(whitespace_attacher);
+      GetStyleEngine().RebuildLayoutTree();
       legacy_layout_objects.ForceLegacyLayoutIfNeeded();
     }
   }

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

@@ -298,10 +298,8 @@ void ReattachLegacyLayoutObjectList::ForceLegacyLayoutIfNeeded() {
   for (const LayoutObject* block : blocks_)
     ToElement(*block->GetNode()).LazyReattachIfAttached();
   state_ = State::kForcingLegacyLayout;
-  Element& document_element = *document_->documentElement();
-  document_element.RecalcStyle(kNoChange);
-  WhitespaceAttacher whitespace_attacher;
-  document_element.RebuildLayoutTree(whitespace_attacher);
+  document_->GetStyleEngine().RecalcStyle(kNoChange);
+  document_->GetStyleEngine().RebuildLayoutTree();
   state_ = State::kClosed;
 }
 

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

@@ -6,6 +6,7 @@
 
 #include "third_party/blink/renderer/bindings/core/v8/v8_binding_for_core.h"
 #include "third_party/blink/renderer/core/css/resolver/style_resolver.h"
+#include "third_party/blink/renderer/core/css/style_engine.h"
 #include "third_party/blink/renderer/core/dom/comment.h"
 #include "third_party/blink/renderer/core/dom/element.h"
 #include "third_party/blink/renderer/core/dom/flat_tree_traversal.h"
@@ -37,7 +38,7 @@ class NodeTest : public EditingTestBase {
   LayoutObject* ReattachLayoutTreeForNode(Node& node) {
     node.LazyReattachIfAttached();
     GetDocument().Lifecycle().AdvanceTo(DocumentLifecycle::kInStyleRecalc);
-    GetDocument().documentElement()->RecalcStyle(kNoChange);
+    GetDocument().GetStyleEngine().RecalcStyle(kNoChange);
     PushSelectorFilterAncestors(
         GetDocument().EnsureStyleResolver().GetSelectorFilter(), node);
     ReattachLegacyLayoutObjectList legacy_objects(GetDocument());

third_party/blink/renderer/core/html/html_content_element_test.cc

@@ -5,6 +5,7 @@
 #include "third_party/blink/renderer/core/html/html_content_element.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/blink/renderer/core/css/style_engine.h"
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/dom/shadow_root.h"
 #include "third_party/blink/renderer/core/testing/dummy_page_holder.h"
@@ -38,7 +39,7 @@ TEST_F(HTMLContentElementTest, FallbackRecalcForReattach) {
 
   GetDocument().UpdateDistributionForLegacyDistributedNodes();
   GetDocument().Lifecycle().AdvanceTo(DocumentLifecycle::kInStyleRecalc);
-  GetDocument().documentElement()->RecalcStyle(kNoChange);
+  GetDocument().GetStyleEngine().RecalcStyle(kNoChange);
 
   EXPECT_TRUE(fallback->GetNonAttachedStyle());
 }

third_party/blink/renderer/core/html/html_object_element_test.cc

@@ -5,6 +5,7 @@
 #include "third_party/blink/renderer/core/html/html_object_element.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/blink/renderer/core/css/style_engine.h"
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/dom/shadow_root.h"
 #include "third_party/blink/renderer/core/testing/dummy_page_holder.h"
@@ -38,7 +39,7 @@ TEST_F(HTMLObjectElementTest, FallbackRecalcForReattach) {
 
   object->RenderFallbackContent();
   GetDocument().Lifecycle().AdvanceTo(DocumentLifecycle::kInStyleRecalc);
-  GetDocument().documentElement()->RecalcStyle(kForce);
+  GetDocument().GetStyleEngine().RecalcStyle(kForce);
 
   EXPECT_TRUE(IsHTMLSlotElement(slot));
   EXPECT_TRUE(object->UseFallbackContent());

third_party/blink/renderer/core/html/html_slot_element_test.cc

@@ -7,6 +7,7 @@
 #include <array>
 
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/blink/renderer/core/css/style_engine.h"
 #include "third_party/blink/renderer/core/dom/shadow_root.h"
 #include "third_party/blink/renderer/core/testing/dummy_page_holder.h"
 
@@ -161,7 +162,7 @@ TEST_F(HTMLSlotElementReattachTest, RecalcAssignedNodeStyleForReattach) {
   shadow_span.setAttribute(HTMLNames::styleAttr, "display:block");
 
   GetDocument().Lifecycle().AdvanceTo(DocumentLifecycle::kInStyleRecalc);
-  GetDocument().documentElement()->RecalcStyle(kNoChange);
+  GetDocument().GetStyleEngine().RecalcStyle(kNoChange);
 
   EXPECT_TRUE(shadow_span.GetNonAttachedStyle());
   EXPECT_TRUE(span.GetNonAttachedStyle());

third_party/blink/renderer/core/html/shadow/progress_shadow_element_test.cc

@@ -5,6 +5,7 @@
 #include "third_party/blink/renderer/core/html/shadow/progress_shadow_element.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/blink/renderer/core/css/style_engine.h"
 #include "third_party/blink/renderer/core/dom/document.h"
 #include "third_party/blink/renderer/core/dom/node_computed_style.h"
 #include "third_party/blink/renderer/core/dom/shadow_root.h"
@@ -40,7 +41,7 @@ TEST_F(ProgressShadowElementTest, LayoutObjectIsNeeded) {
 
   progress->LazyReattachIfAttached();
   GetDocument().Lifecycle().AdvanceTo(DocumentLifecycle::kInStyleRecalc);
-  GetDocument().documentElement()->RecalcStyle(kForce);
+  GetDocument().GetStyleEngine().RecalcStyle(kForce);
   EXPECT_TRUE(shadow_element->GetNonAttachedStyle());
 
   scoped_refptr<ComputedStyle> style = shadow_element->StyleForLayoutObject();