--- a/dom/canvas/WebGLFormats.cpp
+++ b/dom/canvas/WebGLFormats.cpp
@@ -794,16 +794,20 @@ FormatUsageAuthority::CreateForWebGL2(gl
     fnAddSizedUnpack(FOO(DEPTH_COMPONENT32F), LOCAL_GL_DEPTH_COMPONENT, LOCAL_GL_FLOAT         );
 
     // DEPTH_STENCIL
     fnAddSizedUnpack(FOO(DEPTH24_STENCIL8 ), LOCAL_GL_DEPTH_STENCIL, LOCAL_GL_UNSIGNED_INT_24_8             );
     fnAddSizedUnpack(FOO(DEPTH32F_STENCIL8), LOCAL_GL_DEPTH_STENCIL, LOCAL_GL_FLOAT_32_UNSIGNED_INT_24_8_REV);
 
 #undef FOO
 
+    SetUsage(ptr, EffectiveFormat::Luminance8Alpha8, false, true);
+    SetUsage(ptr, EffectiveFormat::Luminance8      , false, true);
+    SetUsage(ptr, EffectiveFormat::Alpha8          , false, true);
+
     AddBasicUnsizedFormats(ptr, gl);
 
     return Move(ret);
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////
 
 void