New java ScalingSettings constructors.

Deprecate old constructors. Intended to make java api consistent with
the changes in https://webrtc-review.googlesource.com/c/src/+/46622.

Bug: webrtc:8830
Change-Id: Iadecb5d033b5de841873905af659d8d234b75c7d
Reviewed-on: https://webrtc-review.googlesource.com/49062
Reviewed-by: Sami Kalliomäki <sakal@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21956}

sdk/android/api/org/webrtc/VideoEncoder.java

@@ -96,11 +96,38 @@ public interface VideoEncoder {
     public final Integer low;
     public final Integer high;
 
+    /**
+     * Settings to disable quality based scaling.
+     */
+    public static final ScalingSettings OFF = new ScalingSettings();
+
+    /**
+     * Creates settings to enable quality based scaling.
+     *
+     * @param low Average QP at which to scale up the resolution.
+     * @param high Average QP at which to scale down the resolution.
+     */
+    public ScalingSettings(int low, int high) {
+      this.on = true;
+      this.low = low;
+      this.high = high;
+    }
+
+    private ScalingSettings() {
+      this.on = false;
+      this.low = null;
+      this.high = null;
+    }
+
+    // TODO(bugs.webrtc.org/8830): Below constructors are deprecated.
+    // Default thresholds are going away, so thresholds have to be set
+    // when scaling is on.
     /**
      * Creates quality based scaling setting.
      *
      * @param on True if quality scaling is turned on.
      */
+    @Deprecated
     public ScalingSettings(boolean on) {
       this.on = on;
       this.low = null;
@@ -114,6 +141,7 @@ public interface VideoEncoder {
      * @param low Average QP at which to scale up the resolution.
      * @param high Average QP at which to scale down the resolution.
      */
+    @Deprecated
     public ScalingSettings(boolean on, int low, int high) {
       this.on = on;
       this.low = low;

sdk/android/src/java/org/webrtc/HardwareVideoEncoder.java

@@ -415,7 +415,18 @@ class HardwareVideoEncoder implements VideoEncoder {
   @Override
   public ScalingSettings getScalingSettings() {
     encodeThreadChecker.checkIsOnValidThread();
-    return new ScalingSettings(automaticResizeOn);
+    if (automaticResizeOn) {
+      if (codecType == VideoCodecType.VP8) {
+        final int kLowVp8QpThreshold = 29;
+        final int kHighVp8QpThreshold = 95;
+        return new ScalingSettings(kLowVp8QpThreshold, kHighVp8QpThreshold);
+      } else if (codecType == VideoCodecType.H264) {
+        final int kLowH264QpThreshold = 24;
+        final int kHighH264QpThreshold = 37;
+        return new ScalingSettings(kLowH264QpThreshold, kHighH264QpThreshold);
+      }
+    }
+    return ScalingSettings.OFF;
   }
 
   @Override