Deflake ImageWriterUtilityClient browsertest and clients

chrome/browser/extensions/api/image_writer_private/operation.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/api/image_writer_private/operation.h"
 
 #include <utility>
 
 #include "base/files/file_enumerator.h"
 #include "base/files/file_util.h"
@@ skipping 245 matching lines @@
     return;
   }
   if (!image_writer_client_.get()) {
     image_writer_client_ = new ImageWriterUtilityClient();
     AddCleanUpFunction(base::Bind(&Operation::StopUtilityClient, this));
   }
 }
 
 void Operation::StopUtilityClient() {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
-  BrowserThread::PostTask(
-      BrowserThread::IO,
-      FROM_HERE,
-      base::Bind(&ImageWriterUtilityClient::Shutdown, image_writer_client_));
+  image_writer_client_->Shutdown();
 }
 
 void Operation::WriteImageProgress(int64_t total_bytes, int64_t curr_bytes) {
   DCHECK_CURRENTLY_ON(BrowserThread::FILE);
   if (IsCancelled()) {
     return;
   }
 
   int progress = kProgressComplete * curr_bytes / total_bytes;
 
@@ skipping 98 matching lines @@
   for (std::vector<base::Closure>::iterator it = cleanup_functions_.begin();
        it != cleanup_functions_.end();
        ++it) {
     it->Run();
   }
   cleanup_functions_.clear();
 }
 
 }  // namespace image_writer
 }  // namespace extensions