add ImageShader, sharing code with its Bitmap cousin

gyp/core.gypi

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 # Include this gypi to include all 'core' files
 # The parent gyp/gypi file must define
 #       'skia_src_path'     e.g. skia/trunk/src
 #       'skia_include_path' e.g. skia/trunk/include
 #
 # The skia build defines these in common_variables.gypi
@@ skipping 236 matching lines @@
         '<(skia_src_path)/core/SkXfermodeInterpretation.h',
         '<(skia_src_path)/core/SkYUVPlanesCache.cpp',
         '<(skia_src_path)/core/SkYUVPlanesCache.h',
 
         '<(skia_src_path)/doc/SkDocument.cpp',
 
         '<(skia_src_path)/image/SkImage.cpp',
         '<(skia_src_path)/image/SkImage_Generator.cpp',
 #        '<(skia_src_path)/image/SkImage_Gpu.cpp',
         '<(skia_src_path)/image/SkImage_Raster.cpp',
+        '<(skia_src_path)/image/SkImageShader.cpp',
+        '<(skia_src_path)/image/SkImageShader.h',
         '<(skia_src_path)/image/SkSurface.cpp',
         '<(skia_src_path)/image/SkSurface_Base.h',
 #        '<(skia_src_path)/image/SkSurface_Gpu.cpp',
         '<(skia_src_path)/image/SkSurface_Raster.cpp',
 
         '<(skia_src_path)/pipe/SkGPipeRead.cpp',
         '<(skia_src_path)/pipe/SkGPipeWrite.cpp',
 
         '<(skia_include_path)/core/SkBBHFactory.h',
         '<(skia_include_path)/core/SkBitmap.h',
@@ skipping 136 matching lines @@
         '<(skia_src_path)/pathops/SkPathOpsLine.h',
         '<(skia_src_path)/pathops/SkPathOpsPoint.h',
         '<(skia_src_path)/pathops/SkPathOpsQuad.h',
         '<(skia_src_path)/pathops/SkPathOpsRect.h',
         '<(skia_src_path)/pathops/SkPathOpsTSect.h',
         '<(skia_src_path)/pathops/SkPathOpsTypes.h',
         '<(skia_src_path)/pathops/SkPathWriter.h',
         '<(skia_src_path)/pathops/SkReduceOrder.h',
     ],
 }