FLOG: Add examples/flog_viewer and always show MOJO_DLOG messages

mojo/services/flog/interfaces/flog.mojom

 // 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.
 
 [DartPackage="mojo_services"]
 module mojo.flog;
 
 // Exposed by the log service to enable creation and consumption of logs.
 [ServiceName="mojo::flog::FlogService"]
 interface FlogService {
@@ skipping 18 matching lines @@
       uint32 source_line);
 
   // Logs the creation of a channel.
   LogChannelCreation(int64 time_us, uint32 channel_id, string type_name);
 
   // Logs a message sent to an existing channel.
   LogChannelMessage(int64 time_us, uint32 channel_id, array<uint8> data);
 
   // Logs the deletion of a channel.
   LogChannelDeletion(int64 time_us, uint32 channel_id);
-
-  // TODO(dalesat): Add a method for logging text/file/line
 };
 
 // A reader that reads messages from one or more logs.
 interface FlogReader {
   // Gets entries from the log starting and the specified index (entries are
   // indexed starting at 0). If the log is open, the callback will be called
   // when max_count entries are avaiable starting at start_index. If the log
   // is closed, the callback will be called immediately with as many entries
   // as are available starting at start_index and not exceeding max_count
   // entries.
@@ skipping 37 matching lines @@
 struct FlogChannelCreationEntryDetails {
   string type_name;
 };
 
 struct FlogChannelMessageEntryDetails {
   array<uint8> data;
 };
 
 struct FlogChannelDeletionEntryDetails {
 };