Revert of Remove header dependencies from sequence_checker.h to sequenced_worker_pool.h

net/ssl/channel_id_service.h

Index: net/ssl/channel_id_service.h
diff --git a/net/ssl/channel_id_service.h b/net/ssl/channel_id_service.h
index 5ef37d2c562c3a2a4a7886559b8b5778c5ee4acb..31b302213e4042ff6d9ebb78bbca90004c50739a 100644
--- a/net/ssl/channel_id_service.h
+++ b/net/ssl/channel_id_service.h
@@ -16,12 +16,15 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
-#include "base/task_runner.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/time.h"
 #include "net/base/completion_callback.h"
 #include "net/base/net_export.h"
 #include "net/ssl/channel_id_store.h"
+
+namespace base {
+class TaskRunner;
+}  // namespace base
 
 namespace crypto {
 class ECPrivateKey;