Add out-of-process memory logging stream parsing.

chrome/profiling/memlog_receiver.h

+// Copyright 2017 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 CHROME_PROFILING_MEMLOG_RECEIVER_H_
+#define CHROME_PROFILING_MEMLOG_RECEIVER_H_
+
+#include "base/memory/ref_counted.h"
+#include "chrome/common/profiling/memlog_stream.h"
+#include "chrome/profiling/address.h"
+#include "chrome/profiling/stack.h"
+
+namespace profiling {
+
+class Stack;
+
+// A log receiver is a sink for parsed allocation events. See also
+// MemlogStreamReceiver which is for the unparsed data blocks.
+class MemlogReceiver {
+ public:
+  MemlogReceiver() {}

[awong, 2017/06/19 20:00:13]

Why do we need to declare the default constructor?

Shoudl this have a disallow copy and assign?

[brettw, 2017/06/19 23:29:45]

Because of mistake.
This isn't necessary since you can't copy classes with pure virtual methods.

[brettw, 2017/06/19 23:33:45]

Sorry, forgot to update after our conversation. I talked to Peter. We agreed
doing this is rare in our codebase. Disallowing copy and assign here prevents
derived classes from implementing those functions if they want (the general
discouragement against copying and assigning is now "avoid" (it used to be
"never do")). Ideally one might do protected ones but that's not what the macro
does.

+  virtual ~MemlogReceiver() {}
+
+  virtual void OnHeader(const StreamHeader& header) = 0;
+  virtual void OnAlloc(const AllocPacket& alloc_packet, Stack&& stack) = 0;
+  virtual void OnFree(const FreePacket& free_packet) = 0;
+  virtual void OnComplete() = 0;
+};
+
+}  // namespace profiling
+
+#endif  // CHROME_PROFILING_MEMLOG_RECEIVER_H_