Added a kEchoCancellation constraint to turn off the audio processing.

content/renderer/media/webrtc_local_audio_track_unittest.cc

Index: content/renderer/media/webrtc_local_audio_track_unittest.cc
diff --git a/content/renderer/media/webrtc_local_audio_track_unittest.cc b/content/renderer/media/webrtc_local_audio_track_unittest.cc
index a30786bf1c7e82c2988e501fc28365ed399af749..dd0883aa76ced7e3ab6ea7f8c0d03c2781a90e0b 100644
--- a/content/renderer/media/webrtc_local_audio_track_unittest.cc
+++ b/content/renderer/media/webrtc_local_audio_track_unittest.cc
@@ -169,11 +169,11 @@ class WebRtcLocalAudioTrackTest : public ::testing::Test {
   virtual void SetUp() OVERRIDE {
     params_.Reset(media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
                   media::CHANNEL_LAYOUT_STEREO, 2, 0, 48000, 16, 480);
-    blink::WebMediaConstraints constraints;
+    MockMediaConstraintFactory constraint_factory;
     StreamDeviceInfo device(MEDIA_DEVICE_AUDIO_CAPTURE,
                             std::string(), std::string());
-    capturer_ = WebRtcAudioCapturer::CreateCapturer(-1, device,
-                                                    constraints, NULL);
+    capturer_ = WebRtcAudioCapturer::CreateCapturer(
+        -1, device, constraint_factory.CreateWebMediaConstraints(), NULL);
     capturer_source_ = new MockCapturerSource(capturer_.get());
     EXPECT_CALL(*capturer_source_.get(), OnInitialize(_, capturer_.get(), -1))
         .WillOnce(Return());
@@ -427,11 +427,12 @@ TEST_F(WebRtcLocalAudioTrackTest, ConnectTracksToDifferentCapturers) {
   track_1->AddSink(sink_1.get());
 
   // Create a new capturer with new source with different audio format.
-  blink::WebMediaConstraints constraints;
+  MockMediaConstraintFactory constraint_factory;
   StreamDeviceInfo device(MEDIA_DEVICE_AUDIO_CAPTURE,
                           std::string(), std::string());
   scoped_refptr<WebRtcAudioCapturer> new_capturer(
-      WebRtcAudioCapturer::CreateCapturer(-1, device, constraints, NULL));
+      WebRtcAudioCapturer::CreateCapturer(
+          -1, device, constraint_factory.CreateWebMediaConstraints(), NULL));
   scoped_refptr<MockCapturerSource> new_source(
       new MockCapturerSource(new_capturer.get()));
   EXPECT_CALL(*new_source.get(), OnInitialize(_, new_capturer.get(), -1));