Reland: Enable NV12 VideoFrames on Mac.

media/video/gpu_memory_buffer_video_frame_pool.cc

Index: media/video/gpu_memory_buffer_video_frame_pool.cc
diff --git a/media/video/gpu_memory_buffer_video_frame_pool.cc b/media/video/gpu_memory_buffer_video_frame_pool.cc
index 7ac0cd763324765bc657812752e301031e5e0d7a..e7ffd99332be2d29bb1251968d80001562fbfc2f 100644
--- a/media/video/gpu_memory_buffer_video_frame_pool.cc
+++ b/media/video/gpu_memory_buffer_video_frame_pool.cc
@@ -202,8 +202,7 @@ unsigned ImageInternalFormat(VideoPixelFormat format, size_t plane) {
       return GL_RED_EXT;
     case PIXEL_FORMAT_NV12:
       DCHECK_LE(plane, 1u);
-      DLOG(WARNING) << "NV12 format not supported yet";
-      return 0;  // TODO(andresantoso): Implement extension for NV12.
+      return GL_RGB_YCBCR_420V_CHROMIUM;
     case PIXEL_FORMAT_UYVY:
       DCHECK_EQ(0u, plane);
       return GL_RGB_YCBCR_422_CHROMIUM;