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) {

[tommi (sloooow) - chröme, 2014/04/30 10:58:44]

nit: FromString doesn't quite describe what the function does

[no longer working on chromium, 2014/05/02 12:24:02]

changed it to ConvertStringToBoolean, is it ok?

[tommi (sloooow) - chröme, 2014/05/03 10:26:28]

Yes thanks. that's very clear.

+  std::istringstream iss(string);

[tommi (sloooow) - chröme, 2014/04/30 10:58:44]

using istringstream here is complete overkill!
just compare the string to "True" and "False" and dcheck if it is anything else.

I also suspect that there's a bug here since the values we're going to be
dealing with are (iirc) "True" and "False" and not "true", "false".  Have you
tested this?

[no longer working on chromium, 2014/05/02 12:24:02]

That is what libjingle is using. I discussed this with Per explicitly and we
decided to follow what libjingle is doing to make sure we had the same behavior.
Does this info change your mind? If not, I can switch to compare the string
instead.
 
Does the TEST_F(MediaStreamConstraintsUtilTest, WrongBooleanConstraints) in
media_stream_constraints_util_unittest.cc answer your question?

[tommi (sloooow) - chröme, 2014/05/03 10:26:28]

Well, imho istringstream here is overkill and if you look at the code generated
by this you'll hopefully agree with me.
Here's a very simple implementation that does exactly what you already have but
doesn't do any extra allocations or copies, is easily inlined, in the best case
does only a single strcmp and it's one line shorter :)

bool ConvertStringToBoolean(const std::string& string, bool* value) {
  *value = (string.compare("true") == 0);
  return *value || string.compare("false") == 0;
}
Yes.  I somehow thought that the constants were "True", "False" and not "true",
"false".

[no longer working on chromium, 2014/05/05 12:55:56]

I agree with you, done with changing it to using string comparison.
I am glad that it is sorted out. FYI, JS constraints boolean has to be either
true or false, True, False, TRUE or FALSE will fail the JS code.

+  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);

[tommi (sloooow) - chröme, 2014/04/30 10:58:44]

StringToInt?

[no longer working on chromium, 2014/05/02 12:24:02]

Yes, I think I have already answered this question before. And after the offline
discussion, it seem you misunderstood that it was used for audio constraints.
And I change the names of all the constraint methods, but we will still use
StringToInt.

On 2014/04/17 10:56:41, tommi wrote:
you
me:
If you don't trust my reply, look at the change in media_stream_video_source.cc

+}
+
+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);

[tommi (sloooow) - chröme, 2014/04/30 10:58:44]

StringToInt?

[no longer working on chromium, 2014/05/02 12:24:02]

Ditto.

+}
+
+}  // namespace content