add -Iinclude/private anywhere we have -Isrc/core

gyp/SampleApp.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.
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'variables': {
     #manually set sample_pdf_file_viewer to 1 to have the PdfViewer in SampleApp
     'sample_pdf_file_viewer%': 0,
   },
   'targets': [
     {
       'target_name': 'SampleApp',
       'type': 'executable',
       'include_dirs' : [
+        '../include/private',
         '../src/core',
         '../src/effects', #needed for BlurMask.h
         '../src/gpu', # needed by SkLua.cpp
         '../src/images',
         '../src/lazy',
         '../gm',       # needed to pull gm.h
         '../samplecode', # To pull SampleApp.h and SampleCode.h
         '../src/pipe/utils', # For TiledPipeController
         '../src/utils/debugger',
       ],
@@ skipping 238 matching lines @@
         }],
         [ 'skia_gpu == 1', {
           'dependencies': [
             'gputest.gyp:skgputest',
           ],
         }],
       ],
     },
   ],
 }