Move SkTDArray to private.

gyp/xml.gyp

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'targets': [
     {
       'target_name': 'xml',
       'product_name': 'skia_xml',
       'type': 'static_library',
       'standalone_static_library': 1,
       'dependencies': [
         'skia_lib.gyp:skia_lib',
       ],
       'include_dirs': [
+        '../include/private',
         '../include/xml',
       ],
       'sources': [
         '../include/xml/SkBML_WXMLParser.h',
         '../include/xml/SkBML_XMLParser.h',
         '../include/xml/SkDOM.h',
         '../include/xml/SkXMLParser.h',
         '../include/xml/SkXMLWriter.h',
 
         '../src/xml/SkBML_Verbs.h',
         '../src/xml/SkBML_XMLParser.cpp',
         '../src/xml/SkDOM.cpp',
         '../src/xml/SkXMLParser.cpp',
         '../src/xml/SkXMLPullParser.cpp',
         '../src/xml/SkXMLWriter.cpp',
       ],
       'sources!': [
           '../src/xml/SkXMLPullParser.cpp', #if 0 around class decl in header
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           '../include/xml',
         ],
       },
     },
   ],
 }