Fixed shutdown concurrency issues in FilePathWatcher.

content/common/file_path_watcher/file_path_watcher.cc

Index: content/common/file_path_watcher/file_path_watcher.cc
diff --git a/content/common/file_path_watcher/file_path_watcher.cc b/content/common/file_path_watcher/file_path_watcher.cc
index 19cee5fdea6995a65983945e6bdfbf3c85ca96d3..f40c8c85d4e6593ba1652d8d83d1f0e465ac919f 100644
--- a/content/common/file_path_watcher/file_path_watcher.cc
+++ b/content/common/file_path_watcher/file_path_watcher.cc
@@ -21,19 +21,10 @@ bool FilePathWatcher::Watch(const FilePath& path,
   return impl_->Watch(path, delegate, loop);
 }
 
-FilePathWatcher::PlatformDelegate::PlatformDelegate() {
+FilePathWatcher::PlatformDelegate::PlatformDelegate(): cancelled_(false) {
 }
 
 FilePathWatcher::PlatformDelegate::~PlatformDelegate() {
+  DCHECK(is_cancelled());
 }
 
-void FilePathWatcher::DeletePlatformDelegate::Destruct(
-    const PlatformDelegate* delegate) {
-  scoped_refptr<base::MessageLoopProxy> loop = delegate->message_loop();
-  if (loop.get() == NULL || loop->BelongsToCurrentThread()) {
-    delete delegate;
-  } else {
-    loop->PostNonNestableTask(FROM_HERE,
-                              new DeleteTask<PlatformDelegate>(delegate));
-  }
-}