AEC: Adds a reported_delay_enabled_ flag

Adds a feature to completely turn on or off buffer handling based on reported delay values. During startup, reported delays are controlled differently through, e.g., WEBRTC_UNTRUSTED_DELAY. By default, the feature is enabled giving the same output as before this change.

TESTED=trybots, modules_unittest
R=aluebs@webrtc.org, andrew@webrtc.org, kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12349005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5965 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_processing/echo_cancellation_impl.h

@@ -72,6 +72,7 @@ class EchoCancellationImpl : public EchoCancellation,
   bool stream_has_echo_;
   bool delay_logging_enabled_;
   bool delay_correction_enabled_;
+  bool reported_delay_enabled_;
 };
 
 }  // namespace webrtc