Fix flaky FileFlusherTest.DuplicateRequests

chrome/browser/chromeos/base/file_flusher.cc

 // Copyright 2016 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/chromeos/base/file_flusher.h"
 
+#include <algorithm>
 #include <set>
 
 #include "base/bind.h"
 #include "base/files/file.h"
 #include "base/files/file_enumerator.h"
 #include "base/logging.h"
 #include "base/synchronization/cancellation_flag.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace chromeos {
@@ skipping 44 matching lines @@
   void FinishOnUIThread();
 
   base::WeakPtr<FileFlusher> master_;
   const base::FilePath path_;
   const std::set<base::FilePath> excludes_;
   const FileFlusher::OnFlushCallback on_flush_callback_;
   const base::Closure callback_;
 
   bool started_ = false;
   base::CancellationFlag cancel_flag_;
+  bool finish_scheduled_ = false;
 
   DISALLOW_COPY_AND_ASSIGN(Job);
 };
 
 FileFlusher::Job::Job(const base::WeakPtr<FileFlusher>& master,
                       const base::FilePath& path,
                       const std::vector<base::FilePath>& excludes,
                       const FileFlusher::OnFlushCallback& on_flush_callback,
                       const base::Closure& callback)
     : master_(master),
@@ skipping 55 matching lines @@
     if (!on_flush_callback_.is_null())
       on_flush_callback_.Run(current);
   }
 }
 
 bool FileFlusher::Job::ShouldExclude(const base::FilePath& path) const {
   return excludes_.find(path) != excludes_.end();
 }
 
 void FileFlusher::Job::ScheduleFinish() {
+  if (finish_scheduled_)
+    return;
+
+  finish_scheduled_ = true;
   content::BrowserThread::PostTask(
       content::BrowserThread::UI, FROM_HERE,
       base::Bind(&Job::FinishOnUIThread, base::Unretained(this)));
 }
 
 void FileFlusher::Job::FinishOnUIThread() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
   if (!callback_.is_null())
     callback_.Run();
@@ skipping 20 matching lines @@
   for (auto* job : jobs_) {
     if (path == job->path() || path.IsParent(job->path()))
       job->Cancel();
   }
 
   jobs_.push_back(new Job(weak_factory_.GetWeakPtr(), path, excludes,
                           on_flush_callback_for_test_, callback));
   ScheduleJob();
 }
 
+void FileFlusher::PauseForTest() {
+  DCHECK(std::none_of(jobs_.begin(), jobs_.end(),

[achuithb, 2016/09/15 18:36:56]

Wow, nice. It's like python.

+                      [](const Job* job) { return job->started(); }));
+  paused_for_test_ = true;
+}
+
+void FileFlusher::ResumeForTest() {
+  paused_for_test_ = false;
+  ScheduleJob();
+}
+
 void FileFlusher::ScheduleJob() {
-  if (jobs_.empty())
+  if (jobs_.empty() || paused_for_test_)
     return;
 
   auto* job = jobs_.front();
   if (!job->started())
     job->Start();
 }
 
 void FileFlusher::OnJobDone(FileFlusher::Job* job) {
   for (auto it = jobs_.begin(); it != jobs_.end(); ++it) {
     if (*it == job) {
       jobs_.erase(it);
       break;
     }
   }
 
   ScheduleJob();
 }
 
 }  // namespace chromeos