Add YUV_420_BIPLANAR to gfx::BufferFormat.

ui/gfx/gpu_memory_buffer.cc

Index: ui/gfx/gpu_memory_buffer.cc
diff --git a/ui/gfx/gpu_memory_buffer.cc b/ui/gfx/gpu_memory_buffer.cc
index adb8d98edb71eba492e269ce633616e1dd29d033..4dd4f072a76e38948ec665a1330ef727f2e1688c 100644
--- a/ui/gfx/gpu_memory_buffer.cc
+++ b/ui/gfx/gpu_memory_buffer.cc
@@ -35,6 +35,8 @@ size_t GpuMemoryBuffer::NumberOfPlanes(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;
   }