Add YUV_420_BIPLANAR to gfx::BufferFormat.

ui/gfx/buffer_format_util.cc

Index: ui/gfx/buffer_format_util.cc
diff --git a/ui/gfx/buffer_format_util.cc b/ui/gfx/buffer_format_util.cc
index 61cf26066719d095e131c66e44ba9a3c72ef9dc6..12e67afc783e7c4ca642087f55cd07f9beebe3f3 100644
--- a/ui/gfx/buffer_format_util.cc
+++ b/ui/gfx/buffer_format_util.cc
@@ -21,6 +21,8 @@ size_t NumberOfPlanesForBufferFormat(BufferFormat format) {
     case BufferFormat::RGBX_8888:
     case BufferFormat::BGRA_8888:
       return 1;
+    case BufferFormat::YUV_420_BIPLANAR:
+      return 2;
     case BufferFormat::YUV_420:
       return 3;
   }