Fix the oilpan build break after r367789.

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 34c9f5abb695912b00259e4c94fa0bc5a4a6effe..26dd0bf22e929fc27b81dae7f0c2e29b02cd8197 100644
--- a/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
+++ b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp
@@ -28,10 +28,10 @@ void SlotAssignment::resolveAssignment(const ShadowRoot& shadowRoot)
 {
     m_assignment.clear();
 
-    using Name2Slot = HashMap<AtomicString, HTMLSlotElement*>;
+    using Name2Slot = WillBeHeapHashMap<AtomicString, RefPtrWillBeMember<HTMLSlotElement>>;

[tkent, 2016/01/06 08:41:21]

The original code uses raw pointers, so you may use RawPtrWillBeMember<> instead
of RefPtrWillBeMember<>.
Of course RefPtrWillBeMember works well.

[hayato, 2016/01/06 08:55:51]

Ditto.

     Name2Slot name2slot;
-    HTMLSlotElement* defaultSlot = nullptr;
-    Vector<HTMLSlotElement*> slots;
+    RefPtrWillBeMember<HTMLSlotElement> defaultSlot = nullptr;

[sof, 2016/01/06 08:40:30]

If you really want to keep a RefPtr<> on the non-Oilpan side, then
RefPtrWillBeRawPtr<> is the transition type to use.

If RefPtr<> usage isn't merited, then leaving this as-was (HTMLSlotElement*)
would be appropriate.

[hayato, 2016/01/06 08:55:51]

Done. I reverted this so that it uses a raw pointer.
We do not need to guard a slot here.

+    WillBeHeapVector<RefPtrWillBeMember<HTMLSlotElement>> slots;
 
     // TODO(hayato): Cache slots elements so that we do not have to travese the shadow tree. See ShadowRoot::descendantInsertionPoints()
     for (HTMLSlotElement& slot : Traversal<HTMLSlotElement>::descendantsOf(shadowRoot)) {