[heap] Move StoreBufferRebuilder into the correct header.

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index 33cb0498f3a174c4fc6e0a2da2c303fddc0ce321..13af5e7c3db705c435ebaaee5614a58a9acc0e43 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -419,25 +419,6 @@ class WeakObjectRetainer;
 typedef String* (*ExternalStringTableUpdaterCallback)(Heap* heap,
                                                       Object** pointer);
 
-class StoreBufferRebuilder {
- public:
-  explicit StoreBufferRebuilder(StoreBuffer* store_buffer)
-      : store_buffer_(store_buffer) {}
-
-  void Callback(MemoryChunk* page, StoreBufferEvent event);
-
- private:
-  StoreBuffer* store_buffer_;
-
-  // We record in this variable how full the store buffer was when we started
-  // iterating over the current page, finding pointers to new space.  If the
-  // store buffer overflows again we can exempt the page from the store buffer
-  // by rewinding to this point instead of having to search the store buffer.
-  Object*** start_of_current_page_;
-  // The current page we are scanning in the store buffer iterator.
-  MemoryChunk* current_page_;
-};
-
 
 // A queue of objects promoted during scavenge. Each object is accompanied
 // by it's size to avoid dereferencing a map pointer for scanning.