Added a kEchoCancellation constraint to turn off the audio processing.

content/renderer/media/media_stream_constraints_util.cc

Index: content/renderer/media/media_stream_constraints_util.cc
diff --git a/content/renderer/media/media_stream_constraints_util.cc b/content/renderer/media/media_stream_constraints_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..718cb484c8f41abd1e75119d06ab460a3994d164
--- /dev/null
+++ b/content/renderer/media/media_stream_constraints_util.cc
@@ -0,0 +1,104 @@
+// Copyright 2014 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 "content/renderer/media/media_stream_constraints_util.h"
+
+#include <sstream>
+
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
+#include "third_party/WebKit/public/platform/WebMediaConstraints.h"
+#include "third_party/WebKit/public/platform/WebString.h"
+
+namespace content {
+
+namespace {
+
+// Convert a string ("true", "false") to a boolean.
+bool FromString(const std::string& string, bool* value) {
+  std::istringstream iss(string);
+  iss >> std::boolalpha >> *value;
+  return !iss.fail();
+}
+
+}  // namespace
+
+bool GetConstraintValue(const blink::WebMediaConstraints& constraints,
+                        const std::string& key,
+                        bool* value) {
+  return GetMandatoryConstraintValue(constraints, key, value) ||
+         GetOptionalConstraintValue(constraints, key, value);
+}
+
+bool GetConstraintValue(const blink::WebMediaConstraints& constraints,
+                        const std::string& key,
+                        int* value) {
+  return GetMandatoryConstraintValue(constraints, key, value) ||
+         GetOptionalConstraintValue(constraints, key, value);
+}
+
+bool GetConstraintValue(const blink::WebMediaConstraints& constraints,
+                        const std::string& key,
+                        std::string* value) {
+  blink::WebString value_str;
+  if (!constraints.getMandatoryConstraintValue(base::UTF8ToUTF16(key),
+                                               value_str) &&
+      !constraints.getOptionalConstraintValue(base::UTF8ToUTF16(key),
+                                              value_str)) {
+    return false;
+  }
+
+  *value = value_str.utf8();
+  return true;
+}
+
+bool GetMandatoryConstraintValue(const blink::WebMediaConstraints& constraints,
+                                 const std::string& key,
+                                 bool* value) {
+  blink::WebString value_str;
+  if (!constraints.getMandatoryConstraintValue(base::UTF8ToUTF16(key),
+                                               value_str)) {
+    return false;
+  }
+
+  return FromString(value_str.utf8(), value);
+}
+
+bool GetMandatoryConstraintValue(const blink::WebMediaConstraints& constraints,
+                                 const std::string& key,
+                                 int* value) {
+  blink::WebString value_str;
+  if (!constraints.getMandatoryConstraintValue(base::UTF8ToUTF16(key),
+                                               value_str)) {
+    return false;
+  }
+
+  return base::StringToInt(value_str.utf8(), value);
+}
+
+bool GetOptionalConstraintValue(const blink::WebMediaConstraints& constraints,
+                                const std::string& key,
+                                bool* value) {
+  blink::WebString value_str;
+  if (!constraints.getOptionalConstraintValue(base::UTF8ToUTF16(key),
+                                              value_str)) {
+    return false;
+  }
+
+  return FromString(value_str.utf8(), value);
+}
+
+bool GetOptionalConstraintValue(const blink::WebMediaConstraints& constraints,
+                                const std::string& key,
+                                int* value) {
+  blink::WebString value_str;
+  if (!constraints.getOptionalConstraintValue(base::UTF8ToUTF16(key),
+                                              value_str)) {
+    return false;
+  }
+
+  return base::StringToInt(value_str.utf8(), value);
+}
+
+}  // namespace content