Include shadow host in elements invalidated by type ruleset invalidations.

When we do a ruleset invalidation for a shadow scope, we schedule an
invalidation set for type selectors on the shadow root node.
This set might also contain tag names for type selectors in :host().
In order to invalidate host elements properly, check if the host's tag name is
contained in any of the type invalidation sets and mark it for style recalc.

Bug: 754191
Change-Id: I92b5a5dfacb86e65ff52247db34fbc9fa0b2101d
Reviewed-on: https://chromium-review.googlesource.com/618069
Commit-Queue: Eriko Kurimoto <elkurin@google.com>
Reviewed-by: Rune Lillesveen <rune@opera.com>
Reviewed-by: Takayoshi Kochi <kochi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#496561}

third_party/WebKit/Source/core/css/invalidation/InvalidationSet.cpp

@@ -108,6 +108,17 @@ bool InvalidationSet::InvalidatesElement(Element& element) const {
   return false;
 }
 
+bool InvalidationSet::InvalidatesTagName(Element& element) const {
+  if (tag_names_ && tag_names_->Contains(element.TagQName().LocalName())) {
+    TRACE_STYLE_INVALIDATOR_INVALIDATION_SELECTORPART_IF_ENABLED(
+        element, kInvalidationSetMatchedTagName, *this,
+        element.TagQName().LocalName());
+    return true;
+  }
+
+  return false;
+}
+
 void InvalidationSet::Combine(const InvalidationSet& other) {
   CHECK(is_alive_);
   CHECK(other.is_alive_);

third_party/WebKit/Source/core/css/invalidation/InvalidationSet.h

@@ -99,6 +99,7 @@ class CORE_EXPORT InvalidationSet {
   static void CacheTracingFlag();
 
   bool InvalidatesElement(Element&) const;
+  bool InvalidatesTagName(Element&) const;
 
   void AddClass(const AtomicString& class_name);
   void AddId(const AtomicString& id);

third_party/WebKit/Source/core/dom/StyleEngine.cpp

@@ -890,6 +890,22 @@ void StyleEngine::ScheduleTypeRuleSetInvalidations(
                                                         node);
   DCHECK(invalidation_lists.siblings.IsEmpty());
   style_invalidator_.ScheduleInvalidationSetsForNode(invalidation_lists, node);
+
+  if (!node.IsShadowRoot())
+    return;
+
+  Element& host = ToShadowRoot(node).host();
+  if (host.NeedsStyleRecalc())
+    return;
+
+  for (auto& invalidation_set : invalidation_lists.descendants) {
+    if (invalidation_set->InvalidatesTagName(host)) {
+      host.SetNeedsStyleRecalc(kLocalStyleChange,
+                               StyleChangeReasonForTracing::Create(
+                                   StyleChangeReason::kStyleSheetChange));
+      return;
+    }
+  }
 }
 
 void StyleEngine::InvalidateSlottedElements(HTMLSlotElement& slot) {

third_party/WebKit/Source/core/dom/StyleEngineTest.cpp

@@ -266,6 +266,9 @@ TEST_F(StyleEngineTest, RuleSetInvalidationHost) {
   GetDocument().View()->UpdateAllLifecyclePhases();
   after_count = GetStyleEngine().StyleForElementCount();
   EXPECT_EQ(1u, after_count - before_count);
+  EXPECT_EQ(ScheduleInvalidationsForRules(*shadow_root,
+                                          ":host(div) { background: green}"),
+            kRuleSetInvalidationsScheduled);
 
   EXPECT_EQ(ScheduleInvalidationsForRules(*shadow_root,
                                           ":host(*) { background: green}"),