Require FilePathWatcher destructor to be called in sequence with Watch().

chrome/common/service_process_util.h

Index: chrome/common/service_process_util.h
diff --git a/chrome/common/service_process_util.h b/chrome/common/service_process_util.h
index 2c20ec0c7d51624b2f45d017d389dcb178c56596..c264742c9c6c71565f5669027b61973d3f4a8e8a 100644
--- a/chrome/common/service_process_util.h
+++ b/chrome/common/service_process_util.h
@@ -9,8 +9,10 @@
 #include <string>
 
 #include "base/callback_forward.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory.h"
 #include "base/process/process.h"
+#include "base/single_thread_task_runner.h"
 #include "build/build_config.h"
 #include "mojo/edk/embedder/named_platform_handle.h"
 #include "mojo/edk/embedder/scoped_platform_handle.h"
@@ -27,7 +29,6 @@ class NSString;
 
 namespace base {
 class CommandLine;
-class SingleThreadTaskRunner;
 }
 
 // Return the IPC channel to connect to the service process.
@@ -91,7 +92,7 @@ class ServiceProcessState {
   // process (in the same thread that called SignalReady). It can be NULL.
   // |task_runner| must be of type IO and is the loop that POSIX uses
   // to monitor the service process.
-  bool SignalReady(base::SingleThreadTaskRunner* task_runner,
+  bool SignalReady(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
                    const base::Closure& terminate_task);
 
   // Signal that the service process is stopped.