Tweak DefaultTrackSelector documentation

Viewport constraints apply to adaptive content even if the
actual playback isn't adaptive (i.e. because the selector
ends up making a fixed track selection).

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=203726831

library/core/src/main/java/com/google/android/exoplayer2/trackselection/DefaultTrackSelector.java

@@ -608,20 +608,20 @@ public class DefaultTrackSelector extends MappingTrackSelector {
      */
     public final boolean exceedVideoConstraintsIfNecessary;
     /**
-     * Viewport width in pixels. Constrains video track selections for adaptive playbacks so that
-     * only tracks suitable for the viewport are selected. The default value is {@link
-     * Integer#MAX_VALUE} (i.e. no constraint).
+     * Viewport width in pixels. Constrains video track selections for adaptive content so that only
+     * tracks suitable for the viewport are selected. The default value is {@link Integer#MAX_VALUE}
+     * (i.e. no constraint).
      */
     public final int viewportWidth;
     /**
-     * Viewport height in pixels. Constrains video track selections for adaptive playbacks so that
+     * Viewport height in pixels. Constrains video track selections for adaptive content so that
      * only tracks suitable for the viewport are selected. The default value is {@link
      * Integer#MAX_VALUE} (i.e. no constraint).
      */
     public final int viewportHeight;
     /**
      * Whether the viewport orientation may change during playback. Constrains video track
-     * selections for adaptive playbacks so that only tracks suitable for the viewport are selected.
+     * selections for adaptive content so that only tracks suitable for the viewport are selected.
      * The default value is {@code true}.
      */
     public final boolean viewportOrientationMayChange;