These files must be in the gypi for GN to remove them...

gyp/utils.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 'utils' 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 17 matching lines @@
         '<(skia_include_path)/utils/SkPaintFilterCanvas.h',
         '<(skia_include_path)/utils/SkParse.h',
         '<(skia_include_path)/utils/SkParsePath.h',
         '<(skia_include_path)/utils/SkPictureUtils.h',
         '<(skia_include_path)/utils/SkRandom.h',
         '<(skia_include_path)/utils/SkRTConf.h',
         '<(skia_include_path)/utils/SkTextBox.h',
 
         '<(skia_src_path)/utils/SkBase64.cpp',
         '<(skia_src_path)/utils/SkBase64.h',
+        '<(skia_src_path)/utils/SkBitmapHasher.cpp',
         '<(skia_src_path)/utils/SkBitmapSourceDeserializer.cpp',
         '<(skia_src_path)/utils/SkBitmapSourceDeserializer.h',
         '<(skia_src_path)/utils/SkBitSet.cpp',
         '<(skia_src_path)/utils/SkBitSet.h',
         '<(skia_src_path)/utils/SkBoundaryPatch.cpp',
         '<(skia_src_path)/utils/SkFrontBufferedStream.cpp',
         '<(skia_src_path)/utils/SkCamera.cpp',
         '<(skia_src_path)/utils/SkCanvasStack.h',
         '<(skia_src_path)/utils/SkCanvasStack.cpp',
         '<(skia_src_path)/utils/SkCanvasStateUtils.cpp',
@@ skipping 19 matching lines @@
         '<(skia_src_path)/utils/SkParse.cpp',
         '<(skia_src_path)/utils/SkParseColor.cpp',
         '<(skia_src_path)/utils/SkParsePath.cpp',
         '<(skia_src_path)/utils/SkPatchGrid.cpp',
         '<(skia_src_path)/utils/SkPatchGrid.h',
         '<(skia_src_path)/utils/SkPatchUtils.cpp',
         '<(skia_src_path)/utils/SkPatchUtils.h',
         '<(skia_src_path)/utils/SkRGBAToYUV.cpp',
         '<(skia_src_path)/utils/SkRGBAToYUV.h',
         '<(skia_src_path)/utils/SkRTConf.cpp',
+        '<(skia_src_path)/utils/SkSHA1.cpp',
         '<(skia_src_path)/utils/SkTextBox.cpp',
         '<(skia_src_path)/utils/SkTextureCompressor.cpp',
         '<(skia_src_path)/utils/SkTextureCompressor.h',
         '<(skia_src_path)/utils/SkTextureCompressor_Utils.h',
         '<(skia_src_path)/utils/SkTextureCompressor_ASTC.cpp',
         '<(skia_src_path)/utils/SkTextureCompressor_ASTC.h',
         '<(skia_src_path)/utils/SkTextureCompressor_Blitter.h',
         '<(skia_src_path)/utils/SkTextureCompressor_R11EAC.cpp',
         '<(skia_src_path)/utils/SkTextureCompressor_R11EAC.h',
         '<(skia_src_path)/utils/SkTextureCompressor_LATC.cpp',
@@ skipping 29 matching lines @@
 
         #testing
         '<(skia_src_path)/fonts/SkGScalerContext.cpp',
         '<(skia_src_path)/fonts/SkGScalerContext.h',
         '<(skia_src_path)/fonts/SkRandomScalerContext.cpp',
         '<(skia_src_path)/fonts/SkRandomScalerContext.h',
         '<(skia_src_path)/fonts/SkTestScalerContext.cpp',
         '<(skia_src_path)/fonts/SkTestScalerContext.h',
     ],
 }