Move SkOSPath out of include/core.

It is moved to src/utils. It is almost a tool, but has two uses in
src/ports.

The existing SkOSFile.cpp is left empty for the time being since it is
mentioned in Chromium's BUILD.gn for Skia.

Change-Id: I3bb7f7c4214359eb6ab906bfe76737d20bf1d6c7
Reviewed-on: https://skia-review.googlesource.com/4536
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 75827ff..8a5927f 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -21,6 +21,7 @@
 #include "SkImage_Base.h"
 #include "SkImageEncoder.h"
 #include "SkOSFile.h"
+#include "SkOSPath.h"
 #include "SkPaint.h"
 #include "SkPaintFilterCanvas.h"
 #include "SkPicture.h"