Tracing V2: Import support for protobuf plugin.

components/tracing/test/example_messages.proto

-// Copyright 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.
-
-syntax = "proto2";
-package foo.bar;
-
-// This file contains comprehensive set of supported message structures and
-// data types. Unit tests depends on the plugin-processed version of this file.
-
-enum SmallEnum {
-  TO_BE = 1;
-  NOT_TO_BE = 0;
-}
-
-enum SignedEnum {
-  POSITIVE = 1;
-  NEUTRAL = 0;
-  NEGATIVE = -1;
-}
-
-enum BigEnum {
-  BEGIN = 10;
-  END = 100500;
-}
-
-message EveryField {
-  optional int32 field_int32 = 1;
-  optional int64 field_int64 = 2;
-  optional uint32 field_uint32 = 3;
-  optional uint64 field_uint64 = 4;
-  optional sint32 field_sint32 = 5;
-  optional sint64 field_sint64 = 6;
-  optional fixed32 field_fixed32 = 7;
-  optional fixed64 field_fixed64 = 8;
-  optional sfixed32 field_sfixed32 = 9;
-  optional sfixed64 field_sfixed64 = 10;
-  optional float field_float = 11;
-  optional double field_double = 12;
-  optional bool field_bool = 13;
-
-  optional SmallEnum small_enum = 51;
-  optional SignedEnum signed_enum = 52;
-  optional BigEnum big_enum = 53;
-
-  optional string field_string = 500;
-  optional bytes field_bytes = 505;
-
-  enum NestedEnum {
-    PING = 1;
-    PONG = 2;
-  }
-  optional NestedEnum nested_enum = 600;
-
-  repeated int32 repeated_int32 = 999;
-}
-
-message NestedA {
-  message NestedB {
-    message NestedC {
-      optional int32 value_c = 1;
-    }
-    optional NestedC value_b = 1;
-  }
-  repeated NestedB repeated_a = 2;
-}