Migrate WTF::Vector::append() to ::push_back() [part 3 of N]

third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp

Index: third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp b/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
index 3bd5f7217f0b17f49faae5da72fb01be578dd1f9..fc2e75dba6a5ff8090223989edabd1a8df5686f3 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/StyleResolver.cpp
@@ -174,7 +174,7 @@ static void collectScopedResolversForHostedShadowTrees(
   for (ShadowRoot* shadowRoot = &shadow->youngestShadowRoot(); shadowRoot;
        shadowRoot = shadowRoot->olderShadowRoot()) {
     if (ScopedStyleResolver* resolver = shadowRoot->scopedStyleResolver())
-      resolvers.append(resolver);
+      resolvers.push_back(resolver);
   }
 }
 
@@ -329,7 +329,7 @@ static void matchSlottedRules(const Element& element,
   HeapVector<Member<ScopedStyleResolver>> resolvers;
   for (; slot; slot = slot->assignedSlot()) {
     if (ScopedStyleResolver* resolver = slot->treeScope().scopedStyleResolver())
-      resolvers.append(resolver);
+      resolvers.push_back(resolver);
   }
   for (auto it = resolvers.rbegin(); it != resolvers.rend(); ++it) {
     collector.clearMatchedRules();
@@ -1203,7 +1203,7 @@ StyleRuleKeyframes* StyleResolver::findKeyframesRule(
   collectScopedResolversForHostedShadowTrees(*element, resolvers);
   if (ScopedStyleResolver* scopedResolver =
           element->treeScope().scopedStyleResolver())
-    resolvers.append(scopedResolver);
+    resolvers.push_back(scopedResolver);
 
   for (auto& resolver : resolvers) {
     if (StyleRuleKeyframes* keyframesRule =