Rewrite SkTRegistry to take any trivially-copyable type.

gm/gm.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 using namespace skiagm;
 
@@ skipping 45 matching lines @@
 void GM::drawSizeBounds(SkCanvas* canvas, SkColor color) {
     SkISize size = this->getISize();
     SkRect r = SkRect::MakeWH(SkIntToScalar(size.width()),
                               SkIntToScalar(size.height()));
     SkPaint paint;
     paint.setColor(color);
     canvas->drawRect(r, paint);
 }
 
 // need to explicitly declare this, or we get some weird infinite loop llist
-template GMRegistry* SkTRegistry<GM*, void*>::gHead;
+template GMRegistry* SkTRegistry<GM*(*)(void*)>::gHead;