Start action processing asynchronously in UpdateAttempter.

update_attempter.h

Index: update_attempter.h
diff --git a/update_attempter.h b/update_attempter.h
index 0afe7f6ba68b4c9c93754523201730dea20c9521..e41cab920c058a485e54cec53a086cbf6ecfe541 100644
--- a/update_attempter.h
+++ b/update_attempter.h
@@ -158,6 +158,9 @@ class UpdateAttempter : public ActionProcessorDelegate,
   static gboolean StaticManagePriorityCallback(gpointer data);
   bool ManagePriorityCallback();
 
+  // Callback to start the action processor.
+  static gboolean StaticStartProcessing(gpointer data);
+
   // Checks if a full update is needed and forces it by updating the Omaha
   // request params.
   void DisableDeltaUpdateIfNeeded();