Added a kEchoCancellation constraint to turn off the audio processing.

content/renderer/media/mock_media_constraint_factory.cc

Index: content/renderer/media/mock_media_constraint_factory.cc
diff --git a/content/renderer/media/mock_media_constraint_factory.cc b/content/renderer/media/mock_media_constraint_factory.cc
index 99d9f56244b49030173e76e88303b1c6eb246355..5708d50bf2f1e061da480cdbcbfa729a2795df4c 100644
--- a/content/renderer/media/mock_media_constraint_factory.cc
+++ b/content/renderer/media/mock_media_constraint_factory.cc
@@ -9,6 +9,13 @@
 
 namespace content {
 
+namespace {
+
+static const char kValueTrue[] = "true";
+static const char kValueFalse[] = "false";
+
+}  // namespace
+
 MockMediaConstraintFactory::MockMediaConstraintFactory() {
 }
 
@@ -37,6 +44,18 @@ void MockMediaConstraintFactory::AddMandatory(const std::string& key,
       base::UTF8ToUTF16(base::DoubleToString(value))));
 }
 
+void MockMediaConstraintFactory::AddMandatory(const std::string& key,
+                                              const std::string& value) {
+  mandatory_.push_back(blink::WebMediaConstraint(
+      base::UTF8ToUTF16(key), base::UTF8ToUTF16(value)));
+}
+
+void MockMediaConstraintFactory::AddMandatory(const std::string& key,
+                                              bool value) {
+  const std::string string_value = value ? kValueTrue : kValueFalse;
+  AddMandatory(key, string_value);
+}
+
 void MockMediaConstraintFactory::AddOptional(const std::string& key,
                                              int value) {
   optional_.push_back(blink::WebMediaConstraint(base::UTF8ToUTF16(key),
@@ -50,6 +69,18 @@ void MockMediaConstraintFactory::AddOptional(const std::string& key,
       base::UTF8ToUTF16(base::DoubleToString(value))));
 }
 
+void MockMediaConstraintFactory::AddOptional(const std::string& key,
+                                             const std::string& value) {
+  optional_.push_back(blink::WebMediaConstraint(
+      base::UTF8ToUTF16(key), base::UTF8ToUTF16(value)));
+}
+
+void MockMediaConstraintFactory::AddOptional(const std::string& key,
+                                              bool value) {
+  const std::string string_value = value ? kValueTrue : kValueFalse;
+  AddOptional(key, string_value);
+}
+
 void MockMediaConstraintFactory::DisableDefaultAudioConstraints() {
   static const char* kDefaultAudioConstraints[] = {
       webrtc::MediaConstraintsInterface::kEchoCancellation,
@@ -62,7 +93,7 @@ void MockMediaConstraintFactory::DisableDefaultAudioConstraints() {
       webrtc::MediaConstraintsInterface::kExperimentalNoiseSuppression
   };
   MockMediaConstraintFactory factory;
-  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kDefaultAudioConstraints); ++i) {
+  for (size_t i = 0; i < arraysize(kDefaultAudioConstraints); ++i) {
     AddMandatory(kDefaultAudioConstraints[i], false);
   }
 }