Added a level controller initialization value to MediaConstraints.

webrtc/api/localaudiosource.cc

Index: webrtc/api/localaudiosource.cc
diff --git a/webrtc/api/localaudiosource.cc b/webrtc/api/localaudiosource.cc
index 53c426e01119900d5eeb5fd4a5524f2f619e954a..7f9667854682c46d8bb8afae983e4f09490ba272 100644
--- a/webrtc/api/localaudiosource.cc
+++ b/webrtc/api/localaudiosource.cc
@@ -26,14 +26,11 @@ namespace {
 // invalid.
 void FromConstraints(const MediaConstraintsInterface::Constraints& constraints,
                      cricket::AudioOptions* options) {
-  // This design relies on the fact that all the audio constraints are actually
-  // "options", i.e. boolean-valued and always satisfiable.  If the constraints
-  // are extended to include non-boolean values or actual format constraints,
-  // a different algorithm will be required.
+  // Set boolean constarints first.

[tommi, 2016/10/19 11:25:50]

Fix typo

[aleloi, 2016/10/19 13:59:21]

Done.

   struct {
     const char* name;
     rtc::Optional<bool>& value;
-  } key_to_value[] = {
+  } boolean_constraint_key_to_value[] = {

[tommi, 2016/10/19 11:25:50]

Are these changes relevant to the cl?
Maybe it's just fine to leave this part as it was, with the comment etc. As is,
having the new qualifier yet no other map, might just make it more confusing. 

[aleloi, 2016/10/19 13:59:21]

I agree, lets leave it as is.

       {MediaConstraintsInterface::kGoogEchoCancellation,
        options->echo_cancellation},
       {MediaConstraintsInterface::kExtendedFilterEchoCancellation,
@@ -53,19 +50,30 @@ void FromConstraints(const MediaConstraintsInterface::Constraints& constraints,
       {MediaConstraintsInterface::kHighpassFilter, options->highpass_filter},
       {MediaConstraintsInterface::kTypingNoiseDetection,
        options->typing_detection},
-      {MediaConstraintsInterface::kAudioMirroring, options->stereo_swapping}
-  };
+      {MediaConstraintsInterface::kAudioMirroring, options->stereo_swapping}};
 
   for (const auto& constraint : constraints) {
     bool value = false;
     if (!rtc::FromString(constraint.value, &value))
       continue;
 
-    for (auto& entry : key_to_value) {
+    for (auto& entry : boolean_constraint_key_to_value) {
       if (constraint.key.compare(entry.name) == 0)
         entry.value = rtc::Optional<bool>(value);
     }
   }
+
+  // Set non-boolean constraints.
+  std::string value;
+  if (constraints.FindFirst(
+          MediaConstraintsInterface::kLevelControlInitialPeakLevelDBFS,
+          &value)) {
+    float level_control_initial_peak_level_dbfs;
+    if (rtc::FromString(value, &level_control_initial_peak_level_dbfs)) {
+      options->level_control_initial_peak_level_dbfs =
+          rtc::Optional<float>(level_control_initial_peak_level_dbfs);
+    }
+  }
 }
 
 }  // namespace