Chrome-wide echo cancellation: Normalize playback delay calculation

Removing delay correction from audio::MixingGraphImpl::OnMoreData(), since
the delay is not corrected like that in other places, and so we can't
reliably compare it with the control group.

See https://bugs.chromium.org/p/chromium/issues/detail?id=1328769#c3 for
detail.

(cherry picked from commit 40a85a5)

Bug: 1328769
Change-Id: Ieb160b505c91b54aa07eacd7e10c04f3c8f0fbef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3689424
Auto-Submit: Olga Sharonova <olka@chromium.org>
Commit-Queue: Olga Sharonova <olka@chromium.org>
Reviewed-by: Sam Zackrisson <saza@chromium.org>
Commit-Queue: Sam Zackrisson <saza@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1010536}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3687722
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/branch-heads/5060@{#657}
Cr-Branched-From: b83393d-refs/heads/main@{#1002911}

services/audio/mixing_graph_impl.cc

@@ -229,25 +229,21 @@ int MixingGraphImpl::OnMoreData(base::TimeDelta delay,
                      "MixingGraphImpl::OnMoreData", "delay", delay,
                      "delay_timestamp", delay_timestamp);
 
-  // The expected playout time is |delay_timestamp| + |delay|.
-  base::TimeDelta total_delay = delay_timestamp + delay - start_time;
-  if (total_delay < base::TimeDelta())
-    total_delay = base::TimeDelta();
-
   uint32_t frames_delayed = media::AudioTimestampHelper::TimeToFrames(
-      total_delay, output_params_.sample_rate());
+      delay, output_params_.sample_rate());
+
   {
     base::AutoLock scoped_lock(lock_);
     main_converter_.ConvertWithDelay(frames_delayed, dest);
   }
 
   SanitizeOutput(dest);
 
-  on_more_data_cb_.Run(*dest, total_delay);
+  on_more_data_cb_.Run(*dest, delay);
 
-  TRACE_EVENT_END2(TRACE_DISABLED_BY_DEFAULT("audio"),
-                   "MixingGraphImpl::OnMoreData", "total_delay", total_delay,
-                   "frames_delayed", frames_delayed);
+  TRACE_EVENT_END1(TRACE_DISABLED_BY_DEFAULT("audio"),
+                   "MixingGraphImpl::OnMoreData", "frames_delayed",
+                   frames_delayed);
   overtime_logger_->Log(start_time);
   return dest->frames();
 }