Make mojo::internal::Buffer a non-virtual class.

mojo/public/cpp/bindings/lib/fixed_buffer.cc

 // Copyright 2014 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.
 
 #include "mojo/public/cpp/bindings/lib/fixed_buffer.h"
 
-#include <stddef.h>
 #include <stdlib.h>
 
-#include <algorithm>
-
-#include "base/logging.h"
-#include "mojo/public/cpp/bindings/lib/serialization_util.h"
-
 namespace mojo {
 namespace internal {
 
-FixedBuffer::FixedBuffer() : ptr_(nullptr), cursor_(0), size_(0) {}
-
-void FixedBuffer::Initialize(void* memory, size_t size) {
-  DCHECK(size == internal::Align(size));
-
-  ptr_ = static_cast<char*>(memory);
-  cursor_ = 0;
-  size_ = size;
-}
-
-void* FixedBuffer::Allocate(size_t delta) {
-  delta = internal::Align(delta);
-
-  if (delta == 0 || delta > size_ - cursor_) {
-    NOTREACHED();
-    return nullptr;
-  }
-
-  char* result = ptr_ + cursor_;
-  cursor_ += delta;
-
-  return result;
-}
-
 FixedBufferForTesting::FixedBufferForTesting(size_t size) {
-  size_ = internal::Align(size);
+  size = internal::Align(size);
   // Use calloc here to ensure all message memory is zero'd out.
-  ptr_ = static_cast<char*>(calloc(size_, 1));
+  void* ptr = calloc(size, 1);
+  Initialize(ptr, size);
 }
 
 FixedBufferForTesting::~FixedBufferForTesting() {
-  free(ptr_);
+  free(data());
 }
 
 void* FixedBufferForTesting::Leak() {
-  char* ptr = ptr_;
-  ptr_ = nullptr;
-  cursor_ = 0;
-  size_ = 0;
+  void* ptr = data();
+  Initialize(nullptr, 0);
   return ptr;
 }
 
 }  // namespace internal
 }  // namespace mojo