Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp

Index: third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
diff --git a/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
index 6ee8312c6e27b0a1ac53b8d98a7d51a2eb5a4222..4eaa67236e014b4c49e6172efeee6084d7eddb03 100644
--- a/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
+++ b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
@@ -28,13 +28,13 @@ void SlotAssignment::resolveAssignment(ShadowRoot& shadowRoot)
 {
     m_assignment.clear();
 
-    using Name2Slot = WillBeHeapHashMap<AtomicString, RefPtrWillBeMember<HTMLSlotElement>>;
+    using Name2Slot = HeapHashMap<AtomicString, Member<HTMLSlotElement>>;
     Name2Slot name2slot;
     HTMLSlotElement* defaultSlot = nullptr;
 
-    const WillBeHeapVector<RefPtrWillBeMember<HTMLSlotElement>>& slots = shadowRoot.descendantSlots();
+    const HeapVector<Member<HTMLSlotElement>>& slots = shadowRoot.descendantSlots();
 
-    for (RefPtrWillBeMember<HTMLSlotElement> slot : slots) {
+    for (Member<HTMLSlotElement> slot : slots) {
         slot->clearDistribution();
         AtomicString name = slot->fastGetAttribute(HTMLNames::nameAttr);
         if (name.isNull() || name.isEmpty()) {