Make WebGL objects scriptwrappable so that binding integrity checks may be applied to them.

Source/core/html/canvas/EXTDrawBuffers.cpp

Index: Source/core/html/canvas/EXTDrawBuffers.cpp
diff --git a/Source/core/html/canvas/EXTDrawBuffers.cpp b/Source/core/html/canvas/EXTDrawBuffers.cpp
index 714b81b29562bf58327af14ef642adb9c258a859..ebee69d959ea8ef35f76cf657559c9248b1bbcae 100644
--- a/Source/core/html/canvas/EXTDrawBuffers.cpp
+++ b/Source/core/html/canvas/EXTDrawBuffers.cpp
@@ -34,6 +34,7 @@ namespace WebCore {
 EXTDrawBuffers::EXTDrawBuffers(WebGLRenderingContext* context)
     : WebGLExtension(context)
 {
+    ScriptWrappable::init(this);
     context->graphicsContext3D()->getExtensions()->ensureEnabled("GL_EXT_draw_buffers");
 }