Move usage of QualityScaler to ViEEncoder.

webrtc/video/overuse_frame_detector.cc

Index: webrtc/video/overuse_frame_detector.cc
diff --git a/webrtc/video/overuse_frame_detector.cc b/webrtc/video/overuse_frame_detector.cc
index bb89864bb0409f9bbee1a95168697266b9654238..c730898543a0021c8dbd8e0b4997d3439752a33b 100644
--- a/webrtc/video/overuse_frame_detector.cc
+++ b/webrtc/video/overuse_frame_detector.cc
@@ -204,7 +204,7 @@ class OveruseFrameDetector::CheckOveruseTask : public rtc::QueuedTask {
 OveruseFrameDetector::OveruseFrameDetector(
     Clock* clock,
     const CpuOveruseOptions& options,
-    CpuOveruseObserver* observer,
+    ScalingObserverInterface* observer,
     EncodedFrameObserver* encoder_timing,
     CpuOveruseMetricsObserver* metrics_observer)
     : check_overuse_task_(nullptr),
@@ -370,13 +370,13 @@ void OveruseFrameDetector::CheckForOveruse() {
     ++num_overuse_detections_;
 
     if (observer_)
-      observer_->OveruseDetected();
+      observer_->ScaleDown(scale_reason_);
   } else if (IsUnderusing(*metrics_, now)) {
     last_rampup_time_ms_ = now;
     in_quick_rampup_ = true;
 
     if (observer_)
-      observer_->NormalUsage();
+      observer_->ScaleUp(scale_reason_);
   }
 
   int rampup_delay =