Remove RefCountedMallocedMemory, it's not used.

base/memory/ref_counted_memory.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_MEMORY_REF_COUNTED_MEMORY_H_
 #define BASE_MEMORY_REF_COUNTED_MEMORY_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 106 matching lines @@
   std::string& data() { return data_; }
 
  private:
   ~RefCountedString() override;
 
   std::string data_;
 
   DISALLOW_COPY_AND_ASSIGN(RefCountedString);
 };
 
-// An implementation of RefCountedMemory that holds a chunk of memory
-// previously allocated with malloc or calloc, and that therefore must be freed
-// using free().
-class BASE_EXPORT RefCountedMallocedMemory : public base::RefCountedMemory {
- public:
-  RefCountedMallocedMemory(void* data, size_t length);
-
-  // Overridden from RefCountedMemory:
-  const unsigned char* front() const override;
-  size_t size() const override;
-
- private:
-  ~RefCountedMallocedMemory() override;
-
-  unsigned char* data_;
-  size_t length_;
-
-  DISALLOW_COPY_AND_ASSIGN(RefCountedMallocedMemory);
-};
-
 }  // namespace base
 
 #endif  // BASE_MEMORY_REF_COUNTED_MEMORY_H_