Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

components/grpc_support/bidirectional_stream.h

Index: components/grpc_support/bidirectional_stream.h
diff --git a/components/grpc_support/bidirectional_stream.h b/components/grpc_support/bidirectional_stream.h
index d57cd87f4b87aba25dc5a121f27deae6d0f126ab..f2a444d46b3e870d5064c414c5de714a899a4cb9 100644
--- a/components/grpc_support/bidirectional_stream.h
+++ b/components/grpc_support/bidirectional_stream.h
@@ -15,6 +15,10 @@
 #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;