Tidy CrossThreadCopier.h inclusion.

third_party/WebKit/Source/platform/heap/PersistentTest.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "platform/heap/Persistent.h"
 
 #include "platform/ThreadSafeFunctional.h"
-#include "platform/heap/Heap.h"
+#include "platform/heap/Handle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include <memory>
 
 namespace blink {
 namespace {
 
 void preciselyCollectGarbage()
 {
     ThreadHeap::collectGarbage(BlinkGC::NoHeapPointersOnStack, BlinkGC::GCWithSweep, BlinkGC::ForcedGC);
 }
@@ skipping 33 matching lines @@
     EXPECT_EQ(1, counter);
 
     receiver = nullptr;
     preciselyCollectGarbage();
     (*function)();
     EXPECT_EQ(1, counter);
 }
 
 } // namespace
 } // namespace blink