Re-enable ProcessPriorityAfterStoppedAudio test on Windows.

chrome/browser/renderer_host/render_process_host_chrome_browsertest.cc

 // Copyright (c) 2012 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 "base/command_line.h"
 #include "base/macros.h"
 #include "base/path_service.h"
 #include "base/process/process.h"
 #include "base/run_loop.h"
 #include "base/test/test_timeouts.h"
@@ skipping 575 matching lines @@
   base::Process no_audio_process_;
 
   content::WebContents* audio_tab_web_contents_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeRenderProcessHostBackgroundingTest);
 };
 
 // Test to make sure that a process is backgrounded when the audio stops playing
 // from the active tab and there is an immediate tab switch.
-// Disable on Windows due to ongoing flakiness. (crbug.com/616421)
-#if defined(OS_WIN)
-#define MAYBE_ProcessPriorityAfterStoppedAudio \
-  DISABLED_ProcessPriorityAfterStoppedAudio
-#else
-#define MAYBE_ProcessPriorityAfterStoppedAudio ProcessPriorityAfterStoppedAudio
-#endif
 IN_PROC_BROWSER_TEST_F(ChromeRenderProcessHostBackgroundingTest,
-                       MAYBE_ProcessPriorityAfterStoppedAudio) {
+                       ProcessPriorityAfterStoppedAudio) {
   // This test is invalid on platforms that can't background.
   if (!base::Process::CanBackgroundProcesses())
     return;
 
   ShowSingletonTab(audio_url_);
 
   // Wait until the no audio page is backgrounded and the audio page is not
   // backgrounded.
   while (!no_audio_process_.IsProcessBackgrounded() ||
          audio_process_.IsProcessBackgrounded()) {
@@ skipping 71 matching lines @@
       content::ExecuteScript(audio_tab_web_contents_,
                              "document.getElementById('audioPlayer').play();"));
 
   // Wait until the two pages are not backgrounded.
   while (no_audio_process_.IsProcessBackgrounded() ||
          audio_process_.IsProcessBackgrounded()) {
     base::RunLoop().RunUntilIdle();
     base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
   }
 }