Remove unused enum (kStatsValueNameEchoCancellationQualityMin).

Removing enum that was left behind when the metric aec_quality_min was
removed.

Bug: webrtc:8563
Change-Id: I8a8c68659abc6465ef42f002f73bd2607e953ac5
Reviewed-on: https://webrtc-review.googlesource.com/33004
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21321}
diff --git a/api/statstypes.cc b/api/statstypes.cc
index ff70bac..d1637e3 100644
--- a/api/statstypes.cc
+++ b/api/statstypes.cc
@@ -487,8 +487,6 @@
       return "googDerBase64";
     case kStatsValueNameDtlsCipher:
       return "dtlsCipher";
-    case kStatsValueNameEchoCancellationQualityMin:
-      return "googEchoCancellationQualityMin";
     case kStatsValueNameEchoDelayMedian:
       return "googEchoCancellationEchoDelayMedian";
     case kStatsValueNameEchoDelayStdDev:
diff --git a/api/statstypes.h b/api/statstypes.h
index 80f0eb5..a034017 100644
--- a/api/statstypes.h
+++ b/api/statstypes.h
@@ -163,7 +163,6 @@
     kStatsValueNameDecodingPLCCNG,
     kStatsValueNameDer,
     kStatsValueNameDtlsCipher,
-    kStatsValueNameEchoCancellationQualityMin,
     kStatsValueNameEchoDelayMedian,
     kStatsValueNameEchoDelayStdDev,
     kStatsValueNameEchoReturnLoss,
diff --git a/pc/statscollector_unittest.cc b/pc/statscollector_unittest.cc
index ffae504..698c175 100644
--- a/pc/statscollector_unittest.cc
+++ b/pc/statscollector_unittest.cc
@@ -1807,9 +1807,6 @@
                         &value_in_report));
   EXPECT_FALSE(GetValue(report, StatsReport::kStatsValueNameJitterReceived,
                         &value_in_report));
-  EXPECT_FALSE(GetValue(report,
-                        StatsReport::kStatsValueNameEchoCancellationQualityMin,
-                        &value_in_report));
   EXPECT_FALSE(GetValue(report, StatsReport::kStatsValueNameEchoDelayMedian,
                         &value_in_report));
   EXPECT_FALSE(GetValue(report, StatsReport::kStatsValueNameEchoDelayStdDev,