Move SkTArray to include/private.

TBR=reed
Agreed moving to private is good.

Review URL: https://codereview.chromium.org/1702073002
diff --git a/include/core/SkTextBlob.h b/include/core/SkTextBlob.h
index b0ab892..e43ff74 100644
--- a/include/core/SkTextBlob.h
+++ b/include/core/SkTextBlob.h
@@ -8,10 +8,9 @@
 #ifndef SkTextBlob_DEFINED
 #define SkTextBlob_DEFINED
 
+#include "../private/SkTemplates.h"
 #include "SkPaint.h"
 #include "SkRefCnt.h"
-#include "SkTArray.h"
-#include "SkTDArray.h"
 
 class SkReadBuffer;
 class SkWriteBuffer;