Remove avg encode time from CpuOveruseMetric struct and use value from OnEncodedFrame instead.

BUG=

Review URL: https://codereview.webrtc.org/1278383002

Cr-Commit-Position: refs/heads/master@{#10911}
diff --git a/webrtc/video/send_statistics_proxy_unittest.cc b/webrtc/video/send_statistics_proxy_unittest.cc
index 1bf9814..f098ce2 100644
--- a/webrtc/video/send_statistics_proxy_unittest.cc
+++ b/webrtc/video/send_statistics_proxy_unittest.cc
@@ -288,6 +288,14 @@
   ExpectEqual(expected_, stats);
 }
 
+TEST_F(SendStatisticsProxyTest, OnEncodedFrame) {
+  const int kEncodeTimeMs = 11;
+  statistics_proxy_->OnEncodedFrame(kEncodeTimeMs);
+
+  VideoSendStream::Stats stats = statistics_proxy_->GetStats();
+  EXPECT_EQ(kEncodeTimeMs, stats.avg_encode_time_ms);
+}
+
 TEST_F(SendStatisticsProxyTest, NoSubstreams) {
   uint32_t excluded_ssrc =
       std::max(