Migrate WTF::HashSet::remove() to ::erase() [part 1]

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

Index: third_party/WebKit/Source/core/dom/MutationObserver.cpp
diff --git a/third_party/WebKit/Source/core/dom/MutationObserver.cpp b/third_party/WebKit/Source/core/dom/MutationObserver.cpp
index 8b00d1453f80a749bc13e25cd7d1391a8f29d7f1..85f6ebac2e8955a11ddc2b3e4dc57e9800b2a37f 100644
--- a/third_party/WebKit/Source/core/dom/MutationObserver.cpp
+++ b/third_party/WebKit/Source/core/dom/MutationObserver.cpp
@@ -163,7 +163,7 @@ void MutationObserver::observationStarted(
 void MutationObserver::observationEnded(
     MutationObserverRegistration* registration) {
   DCHECK(m_registrations.contains(registration));
-  m_registrations.remove(registration);
+  m_registrations.erase(registration);
 }
 
 static MutationObserverSet& activeMutationObservers() {
@@ -280,7 +280,7 @@ void MutationObserver::resumeSuspendedObservers() {
   copyToVector(suspendedMutationObservers(), suspended);
   for (const auto& observer : suspended) {
     if (!observer->shouldBeSuspended()) {
-      suspendedMutationObservers().remove(observer);
+      suspendedMutationObservers().erase(observer);
       activateObserver(observer);
     }
   }