Remove dead code from update_client::Component.

components/update_client/component.h

Index: components/update_client/component.h
diff --git a/components/update_client/component.h b/components/update_client/component.h
index 99ce74b6a879d5e6e0425fc7274e8f654d198e90..c5cdd4cedc7285bd676402a0f26ac1e5c014cce8 100644
--- a/components/update_client/component.h
+++ b/components/update_client/component.h
@@ -24,14 +24,10 @@
 #include "components/update_client/update_response.h"
 #include "url/gurl.h"
 
-namespace base {
-class SingleThreadTaskRunner;
-}
 
 namespace update_client {
 
 struct CrxUpdateItem;
-class ComponentUnpacker;
 struct UpdateContext;
 
 // Describes a CRX component managed by the UpdateEngine. Each |Component| is
@@ -320,14 +316,6 @@ class Component {
 
     void InstallComplete(int error_category, int error_code, int extra_code1);
 
-    // Posts replies back to the main thread.
-    scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
-
-    // Unpacks one CRX.
-    scoped_refptr<ComponentUnpacker> unpacker_;
-
-    base::FilePath unpack_path_;
-
     DISALLOW_COPY_AND_ASSIGN(StateUpdating);
   };