Rewrite SkTRegistry to take any trivially-copyable type.

Obviously these are all currently function pointers of type T(*)(P) for various
T and P.  In bench refactoring, I'm trying to register a function pointer of
type T(*)(), which can't be done as is (passing P=void doesn't work).  This
also lets us register things like primitives, which is conceivable useful.

BUG=
R=reed@google.com, scroggo@google.com

Review URL: https://codereview.chromium.org/23453031

git-svn-id: http://skia.googlecode.com/svn/trunk@11082 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/gm.h b/gm/gm.h
index 022536d..6cd97b5 100644
--- a/gm/gm.h
+++ b/gm/gm.h
@@ -111,7 +111,7 @@
         bool     fHaveCalledOnceBeforeDraw;
     };
 
-    typedef SkTRegistry<GM*, void*> GMRegistry;
+    typedef SkTRegistry<GM*(*)(void*)> GMRegistry;
 }
 
 #endif