diff -r 000000000000 -r 6474c204b198 content/canvas/src/WebGLVertexAttribData.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/canvas/src/WebGLVertexAttribData.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef WEBGLVERTEXATTRIBDATA_H_
+#define WEBGLVERTEXATTRIBDATA_H_
+
+namespace mozilla {
+
+class WebGLBuffer;
+
+struct WebGLVertexAttribData {
+    // note that these initial values are what GL initializes vertex attribs to
+    WebGLVertexAttribData()
+        : buf(0)
+        , stride(0)
+        , size(4)
+        , divisor(0) // OpenGL ES 3.0 specs paragraphe 6.2 p240
+        , byteOffset(0)
+        , type(LOCAL_GL_FLOAT)
+        , enabled(false)
+        , normalized(false)
+    { }
+
+    WebGLRefPtr<WebGLBuffer> buf;
+    GLuint stride;
+    GLuint size;
+    GLuint divisor;
+    GLuint byteOffset;
+    GLenum type;
+    bool enabled;
+    bool normalized;
+
+    GLuint componentSize() const {
+        switch(type) {
+            case LOCAL_GL_BYTE:
+                return sizeof(GLbyte);
+                break;
+            case LOCAL_GL_UNSIGNED_BYTE:
+                return sizeof(GLubyte);
+                break;
+            case LOCAL_GL_SHORT:
+                return sizeof(GLshort);
+                break;
+            case LOCAL_GL_UNSIGNED_SHORT:
+                return sizeof(GLushort);
+                break;
+            // XXX case LOCAL_GL_FIXED:
+            case LOCAL_GL_FLOAT:
+                return sizeof(GLfloat);
+                break;
+            default:
+                NS_ERROR("Should never get here!");
+                return 0;
+        }
+    }
+
+    GLuint actualStride() const {
+        if (stride) return stride;
+        return size * componentSize();
+    }
+};
+
+} // namespace mozilla
+
+inline void ImplCycleCollectionUnlink(mozilla::WebGLVertexAttribData& aField)
+{
+  aField.buf = nullptr;
+}
+
+inline void
+ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
+                            mozilla::WebGLVertexAttribData& aField,
+                            const char* aName,
+                            uint32_t aFlags = 0)
+{
+  CycleCollectionNoteChild(aCallback, aField.buf.get(), aName, aFlags);
+}
+
+#endif
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