Expose ycbcr_420v_image extension via capabilities.

gpu/command_buffer/tests/gl_unittest.cc

Index: gpu/command_buffer/tests/gl_unittest.cc
diff --git a/gpu/command_buffer/tests/gl_unittest.cc b/gpu/command_buffer/tests/gl_unittest.cc
index 2eb1211531a678b68636bfaeacb3233f946f5610..b7fcad69558712793a8c85613d5db4dce2265300 100644
--- a/gpu/command_buffer/tests/gl_unittest.cc
+++ b/gpu/command_buffer/tests/gl_unittest.cc
@@ -116,6 +116,7 @@ TEST_F(GLTest, FeatureFlagsMatchCapabilities) {
             flags.blend_equation_advanced_coherent);
   EXPECT_EQ(caps.texture_rg, flags.ext_texture_rg);
   EXPECT_EQ(caps.image_ycbcr_422, flags.chromium_image_ycbcr_422);
+  EXPECT_EQ(caps.image_ycbcr_420v, flags.chromium_image_ycbcr_420v);
   EXPECT_EQ(caps.render_buffer_format_bgra8888,
             flags.ext_render_buffer_format_bgra8888);
   EXPECT_EQ(caps.occlusion_query_boolean, flags.occlusion_query_boolean);