Added a kEchoCancellation constraint to turn off the audio processing.

content/renderer/media/media_stream_audio_processor_options.cc

Index: content/renderer/media/media_stream_audio_processor_options.cc
diff --git a/content/renderer/media/media_stream_audio_processor_options.cc b/content/renderer/media/media_stream_audio_processor_options.cc
index 320d1a6ba31d8296160a2a67b1c07523aa4d12ef..1707f7dbd6c9e6bb302fcf2b9741a0bd2d71c81c 100644
--- a/content/renderer/media/media_stream_audio_processor_options.cc
+++ b/content/renderer/media/media_stream_audio_processor_options.cc
@@ -7,57 +7,93 @@
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/common/media/media_stream_options.h"
+#include "content/renderer/media/media_stream_constraints_util.h"
 #include "content/renderer/media/rtc_media_constraints.h"
 #include "media/audio/audio_parameters.h"
-#include "third_party/WebKit/public/platform/WebMediaConstraints.h"
-#include "third_party/libjingle/source/talk/app/webrtc/mediaconstraintsinterface.h"
 #include "third_party/webrtc/modules/audio_processing/include/audio_processing.h"
 #include "third_party/webrtc/modules/audio_processing/typing_detection.h"
 
 namespace content {
 
+const char MediaAudioConstraints::kEchoCancellation[] = "echoCancellation";
+const char MediaAudioConstraints::kGoogEchoCancellation[] =
+    "googEchoCancellation";
+const char MediaAudioConstraints::kGoogExperimentalEchoCancellation[] =
+    "googEchoCancellation2";
+const char MediaAudioConstraints::kGoogAutoGainControl[] =
+    "googAutoGainControl";
+const char MediaAudioConstraints::kGoogExperimentalAutoGainControl[] =
+    "googAutoGainControl2";
+const char MediaAudioConstraints::kGoogNoiseSuppression[] =
+    "googNoiseSuppression";
+const char MediaAudioConstraints::kGoogExperimentalNoiseSuppression[] =
+    "googNoiseSuppression2";
+const char MediaAudioConstraints::kGoogHighpassFilter[] = "googHighpassFilter";
+const char MediaAudioConstraints::kGoogTypingNoiseDetection[] =
+    "googTypingNoiseDetection";
+const char MediaAudioConstraints::kGoogAudioMirroring[] = "googAudioMirroring";
+
 namespace {
 
 // Constant constraint keys which enables default audio constraints on
 // mediastreams with audio.
 struct {
   const char* key;
-  const char* value;
+  bool value;
 } const kDefaultAudioConstraints[] = {
-  { webrtc::MediaConstraintsInterface::kEchoCancellation,
-    webrtc::MediaConstraintsInterface::kValueTrue },
+  { MediaAudioConstraints::kEchoCancellation, true },
+  { MediaAudioConstraints::kGoogEchoCancellation, true },
 #if defined(OS_CHROMEOS) || defined(OS_MACOSX)
   // Enable the extended filter mode AEC on platforms with known echo issues.
-  { webrtc::MediaConstraintsInterface::kExperimentalEchoCancellation,
-    webrtc::MediaConstraintsInterface::kValueTrue },
+  { MediaAudioConstraints::kGoogExperimentalEchoCancellation, true },
+#else
+  { MediaAudioConstraints::kGoogExperimentalEchoCancellation, false },
 #endif
-  { webrtc::MediaConstraintsInterface::kAutoGainControl,
-    webrtc::MediaConstraintsInterface::kValueTrue },
-  { webrtc::MediaConstraintsInterface::kExperimentalAutoGainControl,
-    webrtc::MediaConstraintsInterface::kValueTrue },
-  { webrtc::MediaConstraintsInterface::kNoiseSuppression,
-    webrtc::MediaConstraintsInterface::kValueTrue },
-  { webrtc::MediaConstraintsInterface::kHighpassFilter,
-    webrtc::MediaConstraintsInterface::kValueTrue },
-  { webrtc::MediaConstraintsInterface::kTypingNoiseDetection,
-    webrtc::MediaConstraintsInterface::kValueTrue },
+  { MediaAudioConstraints::kGoogAutoGainControl, true },
+  { MediaAudioConstraints::kGoogExperimentalAutoGainControl, true },
+  { MediaAudioConstraints::kGoogNoiseSuppression, true },
+  { MediaAudioConstraints::kGoogHighpassFilter, true },
+  { MediaAudioConstraints::kGoogTypingNoiseDetection, true },
+  { MediaAudioConstraints::kGoogExperimentalNoiseSuppression, false },
 #if defined(OS_WIN)
-  { content::kMediaStreamAudioDucking,
-    webrtc::MediaConstraintsInterface::kValueTrue },
+  { kMediaStreamAudioDucking, true },
+#else
+  { kMediaStreamAudioDucking, false },
 #endif
 };
 
+bool GetDefaultValueForConstraint(const blink::WebMediaConstraints& constraints,
+                                  const std::string& key) {
+  // The default audio processing is false for gUM with a specific
+  // kMediaStreamSource, which is used by tab capture and screen capture.
+  std::string value;
+  if (GetConstraintValue(constraints, kMediaStreamSource, &value))
+    return false;
+
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kDefaultAudioConstraints); ++i) {
+    if (kDefaultAudioConstraints[i].key == key)
+      return kDefaultAudioConstraints[i].value;
+  }
+
+  return false;
+}
+
 } // namespace
 
-void ApplyFixedAudioConstraints(RTCMediaConstraints* constraints) {
+// TODO(xians): Remove this method after the APM in WebRtc is deprecated.
+void MediaAudioConstraints::ApplyFixedAudioConstraints(
+    RTCMediaConstraints* constraints) {
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kDefaultAudioConstraints); ++i) {
     bool already_set_value;
     if (!webrtc::FindConstraint(constraints, kDefaultAudioConstraints[i].key,
                                 &already_set_value, NULL)) {
-      constraints->AddOptional(kDefaultAudioConstraints[i].key,
-          kDefaultAudioConstraints[i].value, false);
+      const std::string value = kDefaultAudioConstraints[i].value ?
+          webrtc::MediaConstraintsInterface::kValueTrue :
+          webrtc::MediaConstraintsInterface::kValueFalse;
+      constraints->AddOptional(kDefaultAudioConstraints[i].key, value, false);
     } else {
       DVLOG(1) << "Constraint " << kDefaultAudioConstraints[i].key
                << " already set to " << already_set_value;
@@ -65,21 +101,18 @@ void ApplyFixedAudioConstraints(RTCMediaConstraints* constraints) {
   }
 }
 
-bool NeedsAudioProcessing(const blink::WebMediaConstraints& constraints,
-                          int effects) {
-  RTCMediaConstraints native_constraints(constraints);
-  ApplyFixedAudioConstraints(&native_constraints);
-  if (effects & media::AudioParameters::ECHO_CANCELLER) {
-    // If platform echo canceller is enabled, disable the software AEC.
-    native_constraints.AddOptional(
-        MediaConstraintsInterface::kEchoCancellation,
-        MediaConstraintsInterface::kValueFalse, true);
-  }
+MediaAudioConstraints::MediaAudioConstraints(
+    const blink::WebMediaConstraints& constraints, int effects)
+    : constraints_(constraints), effects_(effects) {}
+
+MediaAudioConstraints::~MediaAudioConstraints() {}
+
+// TODO(xians): Remove this method after the APM in WebRtc is deprecated.
+bool MediaAudioConstraints::NeedsAudioProcessing() {
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(kDefaultAudioConstraints); ++i) {
-    bool value = false;
-    if (webrtc::FindConstraint(&native_constraints,
-                               kDefaultAudioConstraints[i].key, &value, NULL) &&
-        value) {
+    // |kMediaStreamAudioDucking| does not require audio processing.
+    if (kDefaultAudioConstraints[i].key != kMediaStreamAudioDucking &&
+        GetProperty(kDefaultAudioConstraints[i].key)) {
       return true;
     }
   }
@@ -87,10 +120,50 @@ bool NeedsAudioProcessing(const blink::WebMediaConstraints& constraints,
   return false;
 }
 
-bool GetPropertyFromConstraints(const MediaConstraintsInterface* constraints,
-                                const std::string& key) {
+bool MediaAudioConstraints::GetProperty(const std::string& key) {
   bool value = false;
-  return webrtc::FindConstraint(constraints, key, &value, NULL) && value;
+  if (key == kGoogEchoCancellation) {
+    // If platform echo canceller is enabled, disable the software AEC.
+    if (effects_ & media::AudioParameters::ECHO_CANCELLER)

[ajm, 2014/04/24 21:39:12]

You'll need to apply this to kEchoCancellation if you later intend to remove
kGoogEchoCancellation. But then you'll run into a problem with the dual meaning
of kEchoCancellation: you want to disable the AEC, but not all audio processing.

[no longer working on chromium, 2014/04/28 12:42:54]

Yes, I will keep it in mind.

And I think we have to keep kGoogEchoCancellation in our chromium code for a
while before it can be completely deprecated.

+      return false;
+
+    // If |kEchoCancellation| is specified in the constraints, it will
+    // overwrite the value of |kGoogEchoCancellation|.
+    if (GetConstraintValue(constraints_, kEchoCancellation, &value))

[ajm, 2014/04/24 21:39:12]

Not sure we want to make GetProperty this "smart", but I'll leave that up to you
and Tommi.

[tommi (sloooow) - chröme, 2014/04/25 15:09:31]

I don't think that checking kEchoCancellation or kGoogEchoCancellation in this
function is the right thing to do.

I think the function should return whether or not the property was found and set
the value (whether default or not) via an out argument:

bool GetProperty(const std::string& key, bool* value);

[no longer working on chromium, 2014/04/28 12:42:54]

As offline discussed, I added a GetEchoCancellationProperty() method.
But frankly, it requires all the clients of MediaAudioConstraints to explicitly
check if the constraint is kGoogEchoCancellation or not and call different
methods correspondingly. It might a bit more error prone in a way that users
might use the wrong method.
As offline discussed, you probably meant GetConstraintValue() in
media_stream_constraints_util.h, GetProperty() is used by audio only, and the
purpose is to make it easier for the audio processor to get the property of
audio constraints, and no need to know if the constraint is explicitly set.

+      return value;
+  }
+
+  // Return the value if the constraint is specified in |constraints|,
+  // otherwise return the default value.
+  if (!GetConstraintValue(constraints_, key, &value))
+    value = GetDefaultValueForConstraint(constraints_, key);
+
+  return value;
+}
+
+bool MediaAudioConstraints::IsValid() {
+  blink::WebVector<blink::WebMediaConstraint> mandatory;
+  constraints_.getMandatoryConstraints(mandatory);
+  for (size_t i = 0; i < mandatory.size(); ++i) {
+    if (mandatory[i].m_name.utf8() == kMediaStreamSource)
+      continue;
+
+    bool valid = false;
+    for (size_t j = 0; j < ARRAYSIZE_UNSAFE(kDefaultAudioConstraints); ++j) {
+      if (mandatory[i].m_name.utf8() == kDefaultAudioConstraints[j].key) {
+        valid = true;
+        break;
+      }
+    }
+
+    if (!valid) {
+      DLOG(ERROR) << "Invalid MediaStream constraint. Name:"
+                  <<  mandatory[i].m_name.utf8();
+      return false;
+    }
+  }
+
+  return true;
 }
 
 void EnableEchoCancellation(AudioProcessing* audio_processing) {