Oilpan: tidy HeapTest.VectorDestructors

Source/platform/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 4226 matching lines @@
         HeapVector<InlinedVectorObject, 2> vector;
         InlinedVectorObject i1, i2;
         vector.append(i1);
         vector.append(i2);
     }
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
     EXPECT_LE(4, InlinedVectorObject::s_destructorCalls);
 
     InlinedVectorObject::s_destructorCalls = 0;
     {
-        auto const heapObject = new InlinedVectorObjectWrapper();
+        Persistent<InlinedVectorObjectWrapper> vectorWrapper = new InlinedVectorObjectWrapper();
         Heap::collectGarbage(ThreadState::HeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
         EXPECT_EQ(2, InlinedVectorObject::s_destructorCalls);
-        // Force compiler to keep |heapObject| variable on the stack
-        // while collectGarbage() is working.
-        // Otherwise GC would think that it's safe to collect the object.
-        EXPECT_TRUE(heapObject);
     }
     Heap::collectGarbage(ThreadState::NoHeapPointersOnStack, ThreadState::GCWithSweep, Heap::ForcedGC);
     EXPECT_LE(8, InlinedVectorObject::s_destructorCalls);
 }
 
 // TODO(Oilpan): when Vector.h's contiguous container support no longer disables
 // Vector<>s with inline capacity, enable this test.
 #if !defined(ANNOTATE_CONTIGUOUS_CONTAINER)
 TEST(HeapTest, VectorDestructorsWithVtable)
 {
@@ skipping 2015 matching lines @@
 {
     Persistent<ClassWithMember> object = ClassWithMember::create();
     EXPECT_EQ(0, object->traceCount());
     TestMixinAllocatingObject* mixin = TestMixinAllocatingObject::create(object.get());
     EXPECT_TRUE(mixin);
     EXPECT_GT(object->traceCount(), 0);
     EXPECT_GT(mixin->traceCount(), 0);
 }
 
 } // namespace blink