media: replace LUMINANCE_F16 by RG_88 for 9/10-bit h264 videos

cc/resources/platform_color_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/platform_color.h"
 
 #include <stddef.h>
 
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 13 matching lines @@
       case BGRA_8888:
         EXPECT_NE(rgba, PlatformColor::SameComponentOrder(format));
         break;
       // The following formats are not platform colors.
       case ALPHA_8:
       case LUMINANCE_8:
       case RGB_565:
       case RGBA_4444:
       case ETC1:
       case RED_8:
+      case RG_88:
       case LUMINANCE_F16:
         break;
     }
   }
 }
 
 }  // namespace
 }  // namespace cc