Move SkTHash.h to include/private.

include/views/SkOSWindow_Win.h includes it.

To move SkTHash.h to include/private, SkChecksum.h needs to go there too.  To move SkChecksum.h to include/private, SkTLogic needs to go there too.

This adds a bunch of -Iinclude/private to tools.gyp I missed in the last CL.

No public API changes.
TBR=reed@google.com

BUG=skia:4126

Review URL: https://codereview.chromium.org/1260613006
diff --git a/include/views/SkOSWindow_Win.h b/include/views/SkOSWindow_Win.h
index e7bba18..85cfec1 100644
--- a/include/views/SkOSWindow_Win.h
+++ b/include/views/SkOSWindow_Win.h
@@ -10,9 +10,9 @@
 #ifndef SkOSWindow_Win_DEFINED
 #define SkOSWindow_Win_DEFINED
 
-#include "SkWindow.h"
 #include "../../src/core/SkFunction.h"
-#include "../../src/core/SkTHash.h"
+#include "../private/SkTHash.h"
+#include "SkWindow.h"
 
 #if SK_ANGLE
 #include "EGL/egl.h"