Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

components/grpc_support/bidirectional_stream.h

 // 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.
 
 #ifndef COMPONENTS_GRPC_SUPPORT_BIDIRECTIONAL_STREAM_H_
 #define COMPONENTS_GRPC_SUPPORT_BIDIRECTIONAL_STREAM_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "net/http/bidirectional_stream.h"
 #include "net/url_request/url_request_context_getter.h"
 
+namespace tracked_objects {
+class Location;
+}  // namespace tracked_objects
+
 namespace net {
 class HttpRequestHeaders;
 class WrappedIOBuffer;
 }  // namespace net
 
 namespace grpc_support {
 
 // An adapter to net::BidirectionalStream.
 // Created and configured from any thread. Start, ReadData, WriteData and
 // Destroy can be called on any thread (including network thread), and post
@@ skipping 199 matching lines @@
 
   base::WeakPtr<BidirectionalStream> weak_this_;
   base::WeakPtrFactory<BidirectionalStream> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BidirectionalStream);
 };
 
 }  // namespace grpc_support
 
 #endif  // COMPONENTS_GRPC_SUPPORT_BIDIRECTIONAL_STREAM_H_