HDR: Remove ColorInfo.SDR constant

The SDR constant also specified a color space and range, in addition to
C.COLOR_TRANSFER_SDR. However, it turns out that SDR videos may use different color
space and range values, so following prior ExoPlayer conventions to have `null`
mean "generic SDR" is preferable here.

PiperOrigin-RevId: 459296746

library/common/src/main/java/com/google/android/exoplayer2/video/ColorInfo.java

@@ -32,14 +32,6 @@ import org.checkerframework.dataflow.qual.Pure;
 
 /** Stores color info. */
 public final class ColorInfo implements Bundleable {
-  /** Standard Dynamic Range (SDR). */
-  public static final ColorInfo SDR =
-      new ColorInfo(
-          C.COLOR_SPACE_BT709,
-          C.COLOR_RANGE_LIMITED,
-          C.COLOR_TRANSFER_SDR,
-          /* hdrStaticInfo= */ null);
-
   /**
    * Returns the {@link C.ColorSpace} corresponding to the given ISO color primary code, as per
    * table A.7.21.1 in Rec. ITU-T T.832 (03/2009), or {@link Format#NO_VALUE} if no mapping can be

library/transformer/src/main/java/com/google/android/exoplayer2/transformer/VideoTranscodingSamplePipeline.java

@@ -387,7 +387,7 @@ import org.checkerframework.dataflow.qual.Pure;
                   transformationRequest.videoMimeType != null
                       ? transformationRequest.videoMimeType
                       : inputFormat.sampleMimeType)
-              .setColorInfo(fallbackToSdr ? ColorInfo.SDR : inputFormat.colorInfo)
+              .setColorInfo(fallbackToSdr ? null : inputFormat.colorInfo)
               .build();
 
       encoder =