Have bindings layer assume and insist that all interface types are GCed.

third_party/WebKit/Source/modules/webgl/WebGLDrawBuffers.idl

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 10 matching lines @@
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 typedef unsigned long GLenum;
 
 [
     NoInterfaceObject,
     DoNotCheckConstants,
-    GarbageCollected,
     SetWrapperReferenceFrom=canvas,
 ] interface WebGLDrawBuffers {
     const GLenum COLOR_ATTACHMENT0_WEBGL = 0x8CE0;
     const GLenum COLOR_ATTACHMENT1_WEBGL = 0x8CE1;
     const GLenum COLOR_ATTACHMENT2_WEBGL = 0x8CE2;
     const GLenum COLOR_ATTACHMENT3_WEBGL = 0x8CE3;
     const GLenum COLOR_ATTACHMENT4_WEBGL = 0x8CE4;
     const GLenum COLOR_ATTACHMENT5_WEBGL = 0x8CE5;
     const GLenum COLOR_ATTACHMENT6_WEBGL = 0x8CE6;
     const GLenum COLOR_ATTACHMENT7_WEBGL = 0x8CE7;
@@ skipping 21 matching lines @@
     const GLenum DRAW_BUFFER12_WEBGL = 0x8831;
     const GLenum DRAW_BUFFER13_WEBGL = 0x8832;
     const GLenum DRAW_BUFFER14_WEBGL = 0x8833;
     const GLenum DRAW_BUFFER15_WEBGL = 0x8834;
 
     const GLenum MAX_COLOR_ATTACHMENTS_WEBGL = 0x8CDF;
     const GLenum MAX_DRAW_BUFFERS_WEBGL = 0x8824;
 
     void drawBuffersWEBGL(sequence<GLenum> buffers);
 };