[heap] Avoid inclusion of heap internals in v8.h header.

src/heap/heap-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_HEAP_INL_H_
 #define V8_HEAP_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/base/platform/platform.h"
 #include "src/heap/heap.h"
+#include "src/heap/incremental-marking-inl.h"
+#include "src/heap/spaces-inl.h"
 #include "src/heap/store-buffer.h"
 #include "src/heap/store-buffer-inl.h"
 #include "src/heap-profiler.h"
 #include "src/isolate.h"
 #include "src/list-inl.h"
 #include "src/msan.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 660 matching lines @@
 
 void VerifySmisVisitor::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     CHECK((*current)->IsSmi());
   }
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_INL_H_