Make fake audio file playback loop by default.

chrome/browser/media/webrtc_audio_quality_browsertest.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 <stddef.h>
 
 #include <ctime>
 
 #include "base/command_line.h"
 #include "base/files/file_enumerator.h"
@@ skipping 130 matching lines @@
     // The WebAudio-based tests don't care what devices are available to
     // getUserMedia, and the getUserMedia-based tests will play back a file
     // through the fake device using using --use-file-for-fake-audio-capture.
     command_line->AppendSwitch(switches::kUseFakeDeviceForMediaStream);
 
     // Add loopback interface such that there is always connectivity.
     command_line->AppendSwitch(switches::kAllowLoopbackInPeerConnection);
   }
 
   void ConfigureFakeDeviceToPlayFile(const base::FilePath& wav_file_path) {
-    base::CommandLine::ForCurrentProcess()->AppendSwitchPath(
-        switches::kUseFileForFakeAudioCapture, wav_file_path);
+    base::CommandLine::ForCurrentProcess()->AppendSwitchNative(
+        switches::kUseFileForFakeAudioCapture,
+        wav_file_path.value() + FILE_PATH_LITERAL("%noloop"));
   }
 
   void AddAudioFileToWebAudio(const std::string& input_file_relative_url,
                               content::WebContents* tab_contents) {
     // This calls into webaudio.js.
     EXPECT_EQ("ok-added", ExecuteJavascript(
         "addAudioFile('" + input_file_relative_url + "')", tab_contents));
   }
 
   void PlayAudioFileThroughWebAudio(content::WebContents* tab_contents) {
@@ skipping 640 matching lines @@
 }
 
 // Since the AGC is off here there should be no gain at all.
 IN_PROC_BROWSER_TEST_F(MAYBE_WebRtcAudioQualityBrowserTest,
                        MANUAL_TestAutoGainIsOffWithAudioProcessingOff) {
   const char* kAudioCallWithoutAudioProcessing =
       "{audio: { mandatory: { echoCancellation: false } } }";
   ASSERT_NO_FATAL_FAILURE(TestAutoGainControl(
       kReferenceFile, kAudioCallWithoutAudioProcessing, "_no_agc"));
 }