Do not pass unretained pointer to replies

This change fixes an issue when calling PostTaskWithTraitsAndReply with a
reply that has an unretained pointer to the member class. Because of a race in
tests, SmbService would be torn down and the reply would be run with a pointer
to SmbService resulting in a crash.

Bug: chromium:757625
Change-Id: Ide6b8dd4e05032c504152fafab88ec561d40e30a
Reviewed-on: https://chromium-review.googlesource.com/1195845Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587325}

chrome/browser/chromeos/smb_client/smb_file_system.cc

@@ -372,10 +372,9 @@ AbortCallback SmbFileSystem::WriteFile(
 
   const std::vector<uint8_t> data(buffer->data(), buffer->data() + length);
   if (!temp_file_manager_) {
-    SmbTask task =
-        base::BindOnce(base::IgnoreResult(&SmbFileSystem::CallWriteFile),
-                       base::Unretained(this), file_handle, std::move(data),
-                       offset, length, std::move(callback));
+    SmbTask task = base::BindOnce(
+        base::IgnoreResult(&SmbFileSystem::CallWriteFile), AsWeakPtr(),
+        file_handle, std::move(data), offset, length, std::move(callback));
     InitTempFileManagerAndExecuteTask(std::move(task));
     // The call to init temp_file_manager_ will not be abortable since it is
     // asynchronous.

chrome/browser/chromeos/smb_client/smb_service.cc

@@ -299,7 +299,7 @@ void SmbService::SetupTempFileManagerAndCompleteSetup() {
   base::OnceClosure task =
       base::BindOnce(&SmbService::InitTempFileManager, base::Unretained(this));
   base::OnceClosure reply =
-      base::BindOnce(&SmbService::CompleteSetup, base::Unretained(this));
+      base::BindOnce(&SmbService::CompleteSetup, AsWeakPtr());
 
   base::PostTaskWithTraitsAndReply(FROM_HERE, task_traits, std::move(task),
                                    std::move(reply));