Reduce usage of MessageLoopProxy in base/

base/files/file_path_watcher_linux.cc

Index: base/files/file_path_watcher_linux.cc
diff --git a/base/files/file_path_watcher_linux.cc b/base/files/file_path_watcher_linux.cc
index fb5ba6202ae29a8266d9d1685e1d29f15af06b9c..94b155e4c1df0d9f85d7117b7f9efaa168251bca 100644
--- a/base/files/file_path_watcher_linux.cc
+++ b/base/files/file_path_watcher_linux.cc
@@ -28,9 +28,9 @@
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
-#include "base/message_loop/message_loop_proxy.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/synchronization/lock.h"
+#include "base/thread_task_runner_handle.h"
 #include "base/threading/thread.h"
 
 namespace base {
@@ -117,7 +117,7 @@ class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate,
   // Cancel the watch. This unregisters the instance with InotifyReader.
   virtual void Cancel() override;
 
-  // Cleans up and stops observing the message_loop() thread.
+  // Cleans up and stops observing the task_runner() thread.
   virtual void CancelOnMessageLoopThread() override;
 
   // Deletion of the FilePathWatcher will call Cancel() to dispose of this
@@ -346,12 +346,16 @@ void FilePathWatcherImpl::OnFilePathChanged(InotifyReader::Watch fired_watch,
                                             bool created,
                                             bool deleted,
                                             bool is_dir) {
-  if (!message_loop()->BelongsToCurrentThread()) {
-    // Switch to message_loop() to access |watches_| safely.
-    message_loop()->PostTask(
-        FROM_HERE,
-        Bind(&FilePathWatcherImpl::OnFilePathChanged, this,
-             fired_watch, child, created, deleted, is_dir));
+  if (!task_runner()->RunsTasksOnCurrentThread()) {
+    // Switch to task_runner() to access |watches_| safely.
+    task_runner()->PostTask(FROM_HERE,
+                            Bind(&FilePathWatcherImpl::OnFilePathChanged,
+                                 this,
+                                 fired_watch,
+                                 child,
+                                 created,
+                                 deleted,
+                                 is_dir));
     return;
   }
 
@@ -429,7 +433,7 @@ bool FilePathWatcherImpl::Watch(const FilePath& path,
   DCHECK(target_.empty());
   DCHECK(MessageLoopForIO::current());
 
-  set_message_loop(MessageLoopProxy::current());
+  set_task_runner(ThreadTaskRunnerHandle::Get());
   callback_ = callback;
   target_ = path;
   recursive_ = recursive;
@@ -447,23 +451,23 @@ bool FilePathWatcherImpl::Watch(const FilePath& path,
 
 void FilePathWatcherImpl::Cancel() {
   if (callback_.is_null()) {
-    // Watch was never called, or the message_loop() thread is already gone.
+    // Watch was never called, or the task_runner() thread is already gone.
     set_cancelled();
     return;
   }
 
-  // Switch to the message_loop() if necessary so we can access |watches_|.
-  if (!message_loop()->BelongsToCurrentThread()) {
-    message_loop()->PostTask(FROM_HERE,
-                             Bind(&FilePathWatcher::CancelWatch,
-                                  make_scoped_refptr(this)));
+  // Switch to the task_runner() if necessary so we can access |watches_|.
+  if (!task_runner()->RunsTasksOnCurrentThread()) {
+    task_runner()->PostTask(
+        FROM_HERE,
+        Bind(&FilePathWatcher::CancelWatch, make_scoped_refptr(this)));
   } else {
     CancelOnMessageLoopThread();
   }
 }
 
 void FilePathWatcherImpl::CancelOnMessageLoopThread() {
-  DCHECK(message_loop()->BelongsToCurrentThread());
+  DCHECK(task_runner()->RunsTasksOnCurrentThread());
   set_cancelled();
 
   if (!callback_.is_null()) {
@@ -485,9 +489,9 @@ void FilePathWatcherImpl::WillDestroyCurrentMessageLoop() {
 }
 
 void FilePathWatcherImpl::UpdateWatches() {
-  // Ensure this runs on the message_loop() exclusively in order to avoid
+  // Ensure this runs on the task_runner() exclusively in order to avoid
   // concurrency issues.
-  DCHECK(message_loop()->BelongsToCurrentThread());
+  DCHECK(task_runner()->RunsTasksOnCurrentThread());
   DCHECK(HasValidWatchVector());
 
   // Walk the list of watches and update them as we go.