Set overuse detector max frame interval based on target frame rate.

webrtc/video/overuse_frame_detector.h

Index: webrtc/video/overuse_frame_detector.h
diff --git a/webrtc/video/overuse_frame_detector.h b/webrtc/video/overuse_frame_detector.h
index 2fb3104d538dccc756ca9464f61a12f434b8b9d3..29efa1609d6d8a6b2bfac32861183c0dfba19603 100644
--- a/webrtc/video/overuse_frame_detector.h
+++ b/webrtc/video/overuse_frame_detector.h
@@ -68,7 +68,7 @@ class OveruseFrameDetector {
                        AdaptationObserverInterface* overuse_observer,
                        EncodedFrameObserver* encoder_timing_,
                        CpuOveruseMetricsObserver* metrics_observer);
-  ~OveruseFrameDetector();
+  virtual ~OveruseFrameDetector();
 
   // Start to periodically check for overuse.
   void StartCheckForOveruse();
@@ -77,6 +77,13 @@ class OveruseFrameDetector {
   // StartCheckForOveruse has been called.
   void StopCheckForOveruse();
 
+  // Defines the current maximum framerate targeted by the capturer. This is
+  // used to make sure the encode usage percent doesn't drop unduly if the
+  // capturer has quiet periods (for instance caused by screen capturers with
+  // variable capture rate depending on content updates), otherwise we might
+  // experience adaptation toggling.
+  virtual void OnTargetFramerateUpdated(int framerate_fps);
+
   // Called for each captured frame.
   void FrameCaptured(const VideoFrame& frame, int64_t time_when_first_seen_us);
 
@@ -135,6 +142,7 @@ class OveruseFrameDetector {
 
   // Number of pixels of last captured frame.
   int num_pixels_ GUARDED_BY(task_checker_);
+  int max_framerate_ GUARDED_BY(task_checker_);
   int64_t last_overuse_time_ms_ GUARDED_BY(task_checker_);
   int checks_above_threshold_ GUARDED_BY(task_checker_);
   int num_overuse_detections_ GUARDED_BY(task_checker_);