Added a kEchoCancellation constraint to turn off the audio processing.

content/renderer/media/webrtc_audio_capturer_unittest.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 "base/command_line.h"
 #include "base/logging.h"
 #include "content/public/common/content_switches.h"
 #include "content/renderer/media/mock_media_constraint_factory.h"
 #include "content/renderer/media/webrtc/webrtc_local_audio_track_adapter.h"
 #include "content/renderer/media/webrtc_audio_capturer.h"
@@ skipping 142 matching lines @@
   media::AudioParameters params_;
   scoped_refptr<MockCapturerSource> capturer_source_;
   scoped_refptr<WebRtcAudioCapturer> capturer_;
   scoped_ptr<WebRtcLocalAudioTrack> track_;
 };
 
 // Pass the delay value, volume and key_pressed info via capture callback, and
 // those values should be correctly stored and passed to the track.
 TEST_F(WebRtcAudioCapturerTest, VerifyAudioParams) {
   // Use constraints with default settings.
-  blink::WebMediaConstraints constraints;
-  VerifyAudioParams(constraints, true);
+  MockMediaConstraintFactory constraint_factory;
+  VerifyAudioParams(constraint_factory.CreateWebMediaConstraints(), true);
 }
 
 TEST_F(WebRtcAudioCapturerTest, VerifyAudioParamsWithAudioProcessing) {
   EnableAudioTrackProcessing();
   // Turn off the default constraints to verify that the sink will get packets
   // with a buffer size smaller than 10ms.
   MockMediaConstraintFactory constraint_factory;
   constraint_factory.DisableDefaultAudioConstraints();
   VerifyAudioParams(constraint_factory.CreateWebMediaConstraints(), false);
 }
 
 }  // namespace content