--- a/dom/tests/mochitest/general/test_interfaces.html
+++ b/dom/tests/mochitest/general/test_interfaces.html
@@ -1413,39 +1413,39 @@ var interfaceNamesInGlobalScope =
     "WebGLBuffer",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLContextEvent",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLFramebuffer",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLProgram",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "WebGLQuery",
+    //"WebGLQuery",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLRenderbuffer",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLRenderingContext",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "WebGL2RenderingContext",
-// IMPORTANT: Do not change this list without review from a DOM peer!
-    "WebGLSampler",
+    //"WebGL2RenderingContext",
+// IMPORTANT: Do not change this list without review from a DOM peer!
+    //"WebGLSampler",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLShader",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLShaderPrecisionFormat",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "WebGLSync",
+    //"WebGLSync",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLTexture",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "WebGLTransformFeedback",
+    //"WebGLTransformFeedback",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLUniformLocation",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "WebGLVertexArrayObject",
+    //"WebGLVertexArrayObject",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebKitCSSMatrix",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebSocket",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WheelEvent",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "Window",

--- a/dom/webidl/WebGL2RenderingContext.webidl
+++ b/dom/webidl/WebGL2RenderingContext.webidl
@@ -5,31 +5,37 @@
  *
  * The source for this IDL is found at https://www.khronos.org/registry/webgl/specs/latest/2.0
  * This IDL depends on WebGLRenderingContext.webidl
  */
 
 typedef long long GLint64; // Should this be int64?
 typedef unsigned long long GLuint64;
 
+[Pref="webgl.enable-webgl2"]
 interface WebGLQuery {
 };
 
+[Pref="webgl.enable-webgl2"]
 interface WebGLSampler {
 };
 
+[Pref="webgl.enable-webgl2"]
 interface WebGLSync {
 };
 
+[Pref="webgl.enable-webgl2"]
 interface WebGLTransformFeedback {
 };
 
+[Pref="webgl.enable-webgl2"]
 interface WebGLVertexArrayObject {
 };
 
+[Pref="webgl.enable-webgl2"]
 interface WebGL2RenderingContext : WebGLRenderingContext
 {
     const GLenum READ_BUFFER                                   = 0x0C02;
     const GLenum UNPACK_ROW_LENGTH                             = 0x0CF2;
     const GLenum UNPACK_SKIP_ROWS                              = 0x0CF3;
     const GLenum UNPACK_SKIP_PIXELS                            = 0x0CF4;
     const GLenum PACK_ROW_LENGTH                               = 0x0D02;
     const GLenum PACK_SKIP_ROWS                                = 0x0D03;