Add flag for enabling WebRTC AEC debug recordings.

content/renderer/media/media_stream_dependency_factory.cc

Index: content/renderer/media/media_stream_dependency_factory.cc
diff --git a/content/renderer/media/media_stream_dependency_factory.cc b/content/renderer/media/media_stream_dependency_factory.cc
index a7d133bba214c7bd9619ae0bf507ece90c1bd088..e24d9f180b56dd2fd6a852399399d7b581087fcf 100644
--- a/content/renderer/media/media_stream_dependency_factory.cc
+++ b/content/renderer/media/media_stream_dependency_factory.cc
@@ -6,8 +6,10 @@
 
 #include <vector>
 
+#include "base/command_line.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/utf_string_conversions.h"
+#include "content/public/common/content_switches.h"
 #include "content/renderer/media/media_stream_source_extra_data.h"
 #include "content/renderer/media/rtc_media_constraints.h"
 #include "content/renderer/media/rtc_peer_connection_handler.h"
@@ -301,6 +303,14 @@ void MediaStreamDependencyFactory::CreateNativeMediaSources(
       }
     }
 
+    const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+    // TODO(grunell): Change hard coded string to
+    // RTCMediaConstraints::kInternalAecDump when libjingle has been rolled.
+    if (command_line.HasSwitch(switches::kEnableWebRtcAecRecordings)) {
+      native_audio_constraints.AddOptional(
+          "internalAecDump", "true");
+    }
+
     // Creates a LocalAudioSource object which holds audio options.
     source_data->SetLocalAudioSource(
         CreateLocalAudioSource(&native_audio_constraints));