Rename APM Config ReportedDelay to DelayAgnostic

We use this Config struct for enabling/disabling the delay agnostic
AEC. This change renames it to DelayAgnostic for readability reasons.

NOTE: The logic is reversed in this CL. The old ReportedDelay config
turned DA-AEC off, while the new DelayAgnostic turns it on.

The old Config is kept in parallel with the new during a transition
period. This is to avoid problems with API breakages. During this
period, ReportedDelay is disabled or DelayAgnostic is enabled, DA-AEC
is engaged in APM.

BUG=webrtc:4651
R=bjornv@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1211053006

Cr-Commit-Position: refs/heads/master@{#9531}
diff --git a/webrtc/modules/audio_processing/include/audio_processing.h b/webrtc/modules/audio_processing/include/audio_processing.h
index 2163a9e..80b7b4d 100644
--- a/webrtc/modules/audio_processing/include/audio_processing.h
+++ b/webrtc/modules/audio_processing/include/audio_processing.h
@@ -66,11 +66,19 @@
 // and not EchoControlMobile and is set with AudioProcessing::SetExtraOptions().
 // Note that by disabling reported system delays the EchoCancellation may
 // regress in performance.
+// TODO(henrik.lundin): Remove ReportedDelay once DelayAgnostic has
+// propagated through to all channels
+// (https://code.google.com/p/webrtc/issues/detail?id=4651).
 struct ReportedDelay {
   ReportedDelay() : enabled(true) {}
   explicit ReportedDelay(bool enabled) : enabled(enabled) {}
   bool enabled;
 };
+struct DelayAgnostic {
+  DelayAgnostic() : enabled(false) {}
+  explicit DelayAgnostic(bool enabled) : enabled(enabled) {}
+  bool enabled;
+};
 
 // Use to enable experimental gain control (AGC). At startup the experimental
 // AGC moves the microphone volume up to |startup_min_volume| if the current