[IndexedDB] Refactoring to remove ref ptrs and host transaction ids.

content/browser/indexed_db/indexed_db_cursor.h

Index: content/browser/indexed_db/indexed_db_cursor.h
diff --git a/content/browser/indexed_db/indexed_db_cursor.h b/content/browser/indexed_db/indexed_db_cursor.h
index 63cb7967afaf4c67a0c8d333b55fea722223fecc..4857c54b5df0d9f5bda02594d38e12a4d008f23a 100644
--- a/content/browser/indexed_db/indexed_db_cursor.h
+++ b/content/browser/indexed_db/indexed_db_cursor.h
@@ -12,6 +12,7 @@
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "content/browser/indexed_db/indexed_db_backing_store.h"
 #include "content/browser/indexed_db/indexed_db_database.h"
 #include "content/common/indexed_db/indexed_db_key_range.h"
@@ -21,13 +22,13 @@ namespace content {
 
 class IndexedDBTransaction;
 
-class CONTENT_EXPORT IndexedDBCursor
-    : NON_EXPORTED_BASE(public base::RefCounted<IndexedDBCursor>) {
+class CONTENT_EXPORT IndexedDBCursor {
  public:
   IndexedDBCursor(std::unique_ptr<IndexedDBBackingStore::Cursor> cursor,
                   indexed_db::CursorType cursor_type,
                   blink::WebIDBTaskType task_type,
                   IndexedDBTransaction* transaction);
+  ~IndexedDBCursor();
 
   void Advance(uint32_t count, scoped_refptr<IndexedDBCallbacks> callbacks);
   void Continue(std::unique_ptr<IndexedDBKey> key,
@@ -45,6 +46,8 @@ class CONTENT_EXPORT IndexedDBCursor
   }
   void Close();
 
+  void RemoveCursorFromTransaction();
+
   void CursorIterationOperation(std::unique_ptr<IndexedDBKey> key,
                                 std::unique_ptr<IndexedDBKey> primary_key,
                                 scoped_refptr<IndexedDBCallbacks> callbacks,
@@ -58,13 +61,11 @@ class CONTENT_EXPORT IndexedDBCursor
       IndexedDBTransaction* transaction);
 
  private:
-  friend class base::RefCounted<IndexedDBCursor>;
-
-  ~IndexedDBCursor();
-
   blink::WebIDBTaskType task_type_;
   indexed_db::CursorType cursor_type_;
-  const scoped_refptr<IndexedDBTransaction> transaction_;
+
+  // We rely on the transaction calling Close() to clear this.
+  IndexedDBTransaction* transaction_;
 
   // Must be destroyed before transaction_.
   std::unique_ptr<IndexedDBBackingStore::Cursor> cursor_;
@@ -73,6 +74,8 @@ class CONTENT_EXPORT IndexedDBCursor
 
   bool closed_;
 
+  base::WeakPtrFactory<IndexedDBCursor> ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(IndexedDBCursor);
 };