Fix selection of "no audio processing" mode.

content/renderer/media/media_stream_audio_processor_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 <stddef.h>
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/files/file_path.h"
@@ skipping 324 matching lines @@
 
 TEST_F(MediaStreamAudioProcessorTest, ValidateGoodConstraints) {
   MockConstraintFactory constraint_factory;
   // Check that the renderToAssociatedSink constraint is considered valid.
   constraint_factory.basic().renderToAssociatedSink.setExact(true);
   MediaAudioConstraints audio_constraints(
       constraint_factory.CreateWebMediaConstraints(), 0);
   EXPECT_TRUE(audio_constraints.IsValid());
 }
 
+TEST_F(MediaStreamAudioProcessorTest, NoEchoTurnsOffProcessing) {
+  {
+    MockConstraintFactory constraint_factory;
+    MediaAudioConstraints audio_constraints(
+        constraint_factory.CreateWebMediaConstraints(), 0);
+    // The default value for echo cancellation is true, except when all
+    // audio processing has been turned off.
+    EXPECT_TRUE(audio_constraints.default_audio_processing_constraint_value());
+  }
+  // Turning off audio processing via a mandatory constraint.
+  {
+    MockConstraintFactory constraint_factory;
+    constraint_factory.basic().echoCancellation.setExact(false);
+    MediaAudioConstraints audio_constraints(
+        constraint_factory.CreateWebMediaConstraints(), 0);
+    // The default value for echo cancellation is true, except when all
+    // audio processing has been turned off.
+    EXPECT_FALSE(audio_constraints.default_audio_processing_constraint_value());
+  }
+  // Turning off audio processing via an optional constraint.
+  {
+    MockConstraintFactory constraint_factory;
+    constraint_factory.AddAdvanced().echoCancellation.setExact(false);
+    MediaAudioConstraints audio_constraints(
+        constraint_factory.CreateWebMediaConstraints(), 0);
+    EXPECT_FALSE(audio_constraints.default_audio_processing_constraint_value());
+  }
+}
+
 MediaAudioConstraints MakeMediaAudioConstraints(
     const MockConstraintFactory& constraint_factory) {
   return MediaAudioConstraints(constraint_factory.CreateWebMediaConstraints(),
                                AudioParameters::NO_EFFECTS);
 }
 
 TEST_F(MediaStreamAudioProcessorTest, SelectsConstraintsArrayGeometryIfExists) {
   std::vector<webrtc::Point> constraints_geometry(1,
                                                   webrtc::Point(-0.02f, 0, 0));
   constraints_geometry.push_back(webrtc::Point(0.02f, 0, 0));
@@ skipping 195 matching lines @@
   ProcessDataAndVerifyFormat(audio_processor.get(),
                              kAudioProcessingSampleRate,
                              kAudioProcessingNumberOfChannel,
                              kAudioProcessingSampleRate / 100);
   // Set |audio_processor| to NULL to make sure |webrtc_audio_device| outlives
   // |audio_processor|.
   audio_processor = NULL;
 }
 
 }  // namespace content