Remove limit on how often quality scaling downscales.

webrtc/video/vie_encoder.cc

Index: webrtc/video/vie_encoder.cc
diff --git a/webrtc/video/vie_encoder.cc b/webrtc/video/vie_encoder.cc
index 5722d06c1e651a4961896e49e774e83e9ed5218d..343cd4c8f0c3c4d109b31a64244f516cae7c3326 100644
--- a/webrtc/video/vie_encoder.cc
+++ b/webrtc/video/vie_encoder.cc
@@ -32,6 +32,8 @@ namespace webrtc {
 namespace {
 // Time interval for logging frame counts.
 const int64_t kFrameLogIntervalMs = 60000;
+// We will never ask for a resolution lower than this.
+const int kMinPixelsPerFrame = 120 * 90;
 
 // TODO(pbos): Lower these thresholds (to closer to 100%) when we handle
 // pipelining encoders better (multiple input frames before something comes
@@ -176,7 +178,10 @@ class ViEEncoder::VideoSourceProxy {
     // The input video frame size will have a resolution with less than or
     // equal to |max_pixel_count| depending on how the source can scale the
     // input frame size.
-    sink_wants_.max_pixel_count = rtc::Optional<int>((pixel_count * 3) / 5);
+    const int pixels_wanted = (pixel_count * 3) / 5;
+    if (pixels_wanted < kMinPixelsPerFrame)
+      return;
+    sink_wants_.max_pixel_count = rtc::Optional<int>(pixels_wanted);
     sink_wants_.max_pixel_count_step_up = rtc::Optional<int>();
     if (source_)
       source_->AddOrUpdateSink(vie_encoder_, sink_wants_);
@@ -681,8 +686,6 @@ void ViEEncoder::ScaleDown(ScaleReason reason) {
     return;
   switch (reason) {
     case kQuality:
-      if (scale_counter_[reason] >= kMaxQualityDowngrades)
-        return;
       stats_proxy_->OnQualityRestrictedResolutionChanged(true);
       break;
     case kCpu: