[heap] Separate scavenger functionality into own file.

src/heap/scavenger-inl.h

+// Copyright 2015 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_SCAVENGER_INL_H_
+#define V8_HEAP_SCAVENGER_INL_H_
+
+#include "src/heap/scavenger.h"
+
+namespace v8 {
+namespace internal {
+
+void Scavenger::ScavengeObject(HeapObject** p, HeapObject* object) {
+  DCHECK(object->GetIsolate()->heap()->InFromSpace(object));
+
+  // We use the first word (where the map pointer usually is) of a heap
+  // object to record the forwarding pointer.  A forwarding pointer can
+  // point to an old space, the code space, or the to space of the new
+  // generation.
+  MapWord first_word = object->map_word();
+
+  // If the first word is a forwarding address, the object has already been
+  // copied.
+  if (first_word.IsForwardingAddress()) {
+    HeapObject* dest = first_word.ToForwardingAddress();
+    DCHECK(object->GetIsolate()->heap()->InFromSpace(*p));
+    *p = dest;
+    return;
+  }
+
+  Heap::UpdateAllocationSiteFeedback(object, Heap::IGNORE_SCRATCHPAD_SLOT);
+
+  // AllocationMementos are unrooted and shouldn't survive a scavenge
+  DCHECK(object->map() != object->GetHeap()->allocation_memento_map());
+  // Call the slow part of scavenge object.
+  return ScavengeObjectSlow(p, object);
+}
+
+
+// static
+void StaticScavengeVisitor::VisitPointer(Heap* heap, Object** p) {
+  Object* object = *p;
+  if (!heap->InNewSpace(object)) return;
+  Scavenger::ScavengeObject(reinterpret_cast<HeapObject**>(p),
+                            reinterpret_cast<HeapObject*>(object));
+}
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_HEAP_SCAVENGER_INL_H_