proto_zero_plugin [NOT FOR REVIEW].

components/tracing/proto_zero_plugin/proto_zero_generator.h

+// Copyright (c) 2016 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 FASTCPP_GENERATOR_H__
+#define FASTCPP_GENERATOR_H__
+
+#include <string>
+
+#include <google/protobuf/compiler/code_generator.h>

[Primiano Tucci (use gerrit), 2016/07/05 11:30:18]

Can you make this an absolute include? i.e.
#include "third_party/protobuf/...."

+
+namespace google {

[Primiano Tucci (use gerrit), 2016/07/05 11:30:18]

Is it required to put this into the google::protobuf namespace?
If not I'd just put under tracing::proto as I'm putting the rest there.

+namespace protobuf {
+namespace compiler {
+namespace fastcpp {
+
+class LIBPROTOC_EXPORT Generator : public CodeGenerator {

[Primiano Tucci (use gerrit), 2016/07/05 11:30:18]

not sure this needs to be _EXPORTed. 
This seems to be used only by proto_zero_plugin.cc, and I assume plugin.cc and
generator.cc are part of the same linker unit, right?

+ public:
+  Generator() {}

[Primiano Tucci (use gerrit), 2016/07/05 11:30:18]

Don't inline the ctor and dtor.
See
https://www.chromium.org/developers/coding-style/cpp-dos-and-donts#TOC-Stop-i...

+  ~Generator() override {}
+
+  bool Generate(const FileDescriptor* file,

[Primiano Tucci (use gerrit), 2016/07/05 11:30:18]

Add a 
// CodeGenerator implementation.

It's the general pattern when you extend virt methods of a base class, to
explain where they come from.

+                const string& parameter,
+                GeneratorContext* context,
+                string* error) const override;
+};

[Primiano Tucci (use gerrit), 2016/07/05 11:30:18]

DISALLOW_COPY_AND_ASSIGN

+
+}  // namespace fastcpp
+}  // namespace compiler
+}  // namespace protobuf
+}  // namespace google
+#endif  // FASTCPP_GENERATOR_H__