Support for tracing app initialization.

shell/tracer.h

 // Copyright 2015 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 SHELL_TRACER_H_
 #define SHELL_TRACER_H_
 
 #include <stdio.h>
 
 #include <string>
@@ skipping 63 matching lines @@
   // Emits a comma if needed.
   void WriteCommaIfNeeded();
 
   // Writes trace file footer and closes out the file.
   void WriteFooterAndClose();
 
   // Set when connected to the tracing service.
   tracing::TraceCollectorPtr coordinator_;
   scoped_ptr<mojo::common::DataPipeDrainer> drainer_;
 
+  mojo::TraceProviderImpl trace_provider_impl_;
   // Whether we're currently tracing.
   bool tracing_;
   // How long to trace after message loop creation.
   int trace_duration_secs_;
   // Categories to trace.
   std::string categories_;
 
   // Whether we've written the first chunk.
   bool first_chunk_written_;
   std::string trace_service_data_;
 
   // Trace file, if open.
   FILE* trace_file_;
   std::string trace_filename_;
 
   DISALLOW_COPY_AND_ASSIGN(Tracer);
 };
 
 }  // namespace shell
 
 #endif  // SHELL_TRACER_H_