--- a/dom/canvas/WebGLContextGL.cpp
+++ b/dom/canvas/WebGLContextGL.cpp
@@ -1332,110 +1332,16 @@ WebGLContext::DoReadPixelsAndConvert(con
 
     gl->fPixelStorei(LOCAL_GL_PACK_ALIGNMENT, mPixelStore_PackAlignment);
     gl->fPixelStorei(LOCAL_GL_PACK_ROW_LENGTH, mPixelStore_PackRowLength);
     gl->fPixelStorei(LOCAL_GL_PACK_SKIP_ROWS, mPixelStore_PackSkipRows);
     return true;
 }
 
 static bool
-IsFormatAndTypeUnpackable(GLenum format, GLenum type, bool isWebGL2)
-{
-    switch (type) {
-    case LOCAL_GL_UNSIGNED_BYTE:
-        switch (format) {
-        case LOCAL_GL_LUMINANCE:
-        case LOCAL_GL_LUMINANCE_ALPHA:
-            return isWebGL2;
-        case LOCAL_GL_ALPHA:
-        case LOCAL_GL_RED:
-        case LOCAL_GL_RED_INTEGER:
-        case LOCAL_GL_RG:
-        case LOCAL_GL_RG_INTEGER:
-        case LOCAL_GL_RGB:
-        case LOCAL_GL_RGB_INTEGER:
-        case LOCAL_GL_RGBA:
-        case LOCAL_GL_RGBA_INTEGER:
-            return true;
-        default:
-            return false;
-        }
-
-    case LOCAL_GL_BYTE:
-        switch (format) {
-        case LOCAL_GL_RED:
-        case LOCAL_GL_RED_INTEGER:
-        case LOCAL_GL_RG:
-        case LOCAL_GL_RG_INTEGER:
-        case LOCAL_GL_RGB:
-        case LOCAL_GL_RGB_INTEGER:
-        case LOCAL_GL_RGBA:
-        case LOCAL_GL_RGBA_INTEGER:
-            return true;
-        default:
-            return false;
-        }
-
-    case LOCAL_GL_FLOAT:
-    case LOCAL_GL_HALF_FLOAT:
-    case LOCAL_GL_HALF_FLOAT_OES:
-        switch (format) {
-        case LOCAL_GL_RED:
-        case LOCAL_GL_RG:
-        case LOCAL_GL_RGB:
-        case LOCAL_GL_RGBA:
-            return true;
-        default:
-            return false;
-        }
-
-    case LOCAL_GL_UNSIGNED_SHORT_4_4_4_4:
-    case LOCAL_GL_UNSIGNED_SHORT_5_5_5_1:
-        return format == LOCAL_GL_RGBA;
-
-    case LOCAL_GL_UNSIGNED_SHORT_5_6_5:
-        return format == LOCAL_GL_RGB;
-
-    default:
-        return false;
-    }
-}
-
-static bool
-IsIntegerFormatAndTypeUnpackable(GLenum format, GLenum type)
-{
-    switch (type) {
-    case LOCAL_GL_UNSIGNED_SHORT:
-    case LOCAL_GL_SHORT:
-    case LOCAL_GL_UNSIGNED_INT:
-    case LOCAL_GL_INT:
-        switch (format) {
-        case LOCAL_GL_RED_INTEGER:
-        case LOCAL_GL_RG_INTEGER:
-        case LOCAL_GL_RGB_INTEGER:
-        case LOCAL_GL_RGBA_INTEGER:
-            return true;
-        default:
-            return false;
-        }
-
-    case LOCAL_GL_UNSIGNED_INT_2_10_10_10_REV:
-        return format == LOCAL_GL_RGBA ||
-               format == LOCAL_GL_RGBA_INTEGER;
-
-    case LOCAL_GL_UNSIGNED_INT_10F_11F_11F_REV:
-    case LOCAL_GL_UNSIGNED_INT_5_9_9_9_REV:
-        return format == LOCAL_GL_RGB;
-
-    default:
-        return false;
-    }
-}
-
-static bool
 GetJSScalarFromGLType(GLenum type, js::Scalar::Type* const out_scalarType)
 {
     switch (type) {
     case LOCAL_GL_BYTE:
         *out_scalarType = js::Scalar::Int8;
         return true;
 
     case LOCAL_GL_UNSIGNED_BYTE: