[chrome/browser/metrices] Replace MessageLoopProxy usage with ThreadTaskRunnerHandle

chrome/browser/metrics/thread_watcher.h

Index: chrome/browser/metrics/thread_watcher.h
diff --git a/chrome/browser/metrics/thread_watcher.h b/chrome/browser/metrics/thread_watcher.h
index 41dfb9c83ffe9e4ea618200a76fd68b88c6b6df6..f62b04d1be4550771df2db0dbd0b630ca65223a6 100644
--- a/chrome/browser/metrics/thread_watcher.h
+++ b/chrome/browser/metrics/thread_watcher.h
@@ -53,6 +53,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
+#include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread.h"
@@ -219,7 +220,7 @@ class ThreadWatcher {
   const std::string thread_name_;
 
   // Used to post messages to watched thread.
-  scoped_refptr<base::MessageLoopProxy> watched_loop_;
+  scoped_refptr<base::SingleThreadTaskRunner> watched_runner_;
 
   // It is the sleep time between the receipt of a pong message back, and the
   // sending of another ping message.