Oilpan: Fix isAlive dispatching for GarbageCollectedMixins.

Source/heap/HeapTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 157 matching lines @@
 
 private:
     size_t m_count;
 };
 
 class SimpleObject : public GarbageCollected<SimpleObject> {
 public:
     static SimpleObject* create() { return new SimpleObject(); }
     void trace(Visitor*) { }
     char getPayload(int i) { return payload[i]; }
+    virtual void virtualMethod() { }

[Mads Ager (chromium), 2014/04/02 18:13:56]

I'll add a comment that this make sure that the object has a vtable which means
that adjustment becomes needed when a mixin is added in the inheritance
hierarchy.

 protected:
     SimpleObject() { }
     char payload[64];
 };
 
 #undef DEFINE_VISITOR_METHODS
 
 class HeapTestSuperClass : public GarbageCollectedFinalized<HeapTestSuperClass> {
 public:
     static HeapTestSuperClass* create()
@@ skipping 942 matching lines @@
         ++s_aliveCount;
     }
 };
 
 int TransitionRefCounted::s_aliveCount = 0;
 
 class Mixin : public GarbageCollectedMixin {
 public:
     virtual void trace(Visitor* visitor) { }
 
-    char getPayload(int i) { return m_padding[i]; }
+    virtual char getPayload(int i) { return m_padding[i]; }
 
 protected:
-    // This is to force ptr diff for SimpleObject, Mixin, and UseMixin.
     int m_padding[8];
 };
 
 class UseMixin : public SimpleObject, public Mixin {
     USING_GARBAGE_COLLECTED_MIXIN(UseMixin)
 public:
     static UseMixin* create()
     {
         return new UseMixin();
     }
@@ skipping 1822 matching lines @@
     Persistent<HeapHashMap<void*, IntVector> > keepAlive(map);
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);
     EXPECT_EQ(1u, map->get(key).size());
     EXPECT_EQ(0, IntWrapper::s_destructorCalls);
 
     keepAlive = nullptr;
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);
     EXPECT_EQ(1, IntWrapper::s_destructorCalls);
 }
 
-TEST(heap, GarbageCollectedMixin)
+TEST(HeapTest, GarbageCollectedMixin)
 {
     HeapStats initialHeapStats;
     clearOutOldGarbage(&initialHeapStats);
 
     Persistent<UseMixin> usemixin = UseMixin::create();
-    ASSERT_EQ(0, UseMixin::s_traceCount);
+    EXPECT_EQ(0, UseMixin::s_traceCount);
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);
-    ASSERT_EQ(1, UseMixin::s_traceCount);
+    EXPECT_EQ(1, UseMixin::s_traceCount);
 
     Persistent<Mixin> mixin = usemixin;
     usemixin = nullptr;
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);
-    ASSERT_EQ(2, UseMixin::s_traceCount);
+    EXPECT_EQ(2, UseMixin::s_traceCount);
+
+    PersistentHeapHashSet<WeakMember<Mixin> > weakMap;
+    weakMap.add(UseMixin::create());
+    Heap::collectGarbage(ThreadState::NoHeapPointersOnStack);
+    EXPECT_EQ(0u, weakMap.size());
 }
 
 TEST(HeapTest, CollectionNesting2)
 {
     HeapStats initialStats;
     clearOutOldGarbage(&initialStats);
     void* key = &IntWrapper::s_destructorCalls;
     IntWrapper::s_destructorCalls = 0;
     typedef HeapHashSet<Member<IntWrapper> > IntSet;
     HeapHashMap<void*, IntSet>* map = new HeapHashMap<void*, IntSet>();
@@ skipping 206 matching lines @@
 {
     HeapHashMap<SimpleClassWithDestructor*, OwnPtr<SimpleClassWithDestructor> > map;
     SimpleClassWithDestructor* hasDestructor = new SimpleClassWithDestructor();
     map.add(hasDestructor, adoptPtr(hasDestructor));
     SimpleClassWithDestructor::s_wasDestructed = false;
     map.clear();
     ASSERT(SimpleClassWithDestructor::s_wasDestructed);
 }
 
 } // WebCore namespace