Revert "SkTypes: extract SkTo"

This reverts commit 2a2f67592602b18527bc3fd449132d420cd5b62e.

Reason for revert: this appears to be what is holding up the Chrome roll.

Original change's description:
> SkTypes: extract SkTo
>
> Change-Id: I8de790d5013db2105ad885fa2683303d7c250b09
> Reviewed-on: https://skia-review.googlesource.com/133620
> Reviewed-by: Mike Klein <mtklein@google.com>

TBR=mtklein@google.com,halcanary@google.com

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: Iafd738aedfb679a23c061a51afe4b98a8d4cdfae
Reviewed-on: https://skia-review.googlesource.com/134504
Reviewed-by: Hal Canary <halcanary@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/include/gpu/GrResourceKey.h b/include/gpu/GrResourceKey.h
index 90b84d7..0240387 100644
--- a/include/gpu/GrResourceKey.h
+++ b/include/gpu/GrResourceKey.h
@@ -1,3 +1,4 @@
+
 /*
  * Copyright 2014 Google Inc.
  *
@@ -10,7 +11,6 @@
 
 #include "../private/SkOnce.h"
 #include "../private/SkTemplates.h"
-#include "../private/SkTo.h"
 #include "GrTypes.h"
 #include "SkData.h"
 #include "SkString.h"