Add and use SkSemaphore

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
 #
 {
     'sources': [
-        # Classes for a threadpool.
-        '<(skia_src_path)/utils/SkCondVar.h',
-        '<(skia_src_path)/utils/SkRunnable.h',
-        '<(skia_src_path)/utils/SkCondVar.cpp',
-
         '<(skia_include_path)/utils/SkBoundaryPatch.h',
         '<(skia_include_path)/utils/SkFrontBufferedStream.h',
         '<(skia_include_path)/utils/SkCamera.h',
         '<(skia_include_path)/utils/SkCanvasStateUtils.h',
         '<(skia_include_path)/utils/SkCubicInterval.h',
         '<(skia_include_path)/utils/SkCullPoints.h',
         '<(skia_include_path)/utils/SkDebugUtils.h',
         '<(skia_include_path)/utils/SkDeferredCanvas.h',
         '<(skia_include_path)/utils/SkDumpCanvas.h',
         '<(skia_include_path)/utils/SkEventTracer.h',
@@ skipping 100 matching lines @@
         '<(skia_src_path)/utils/win/SkWGL.h',
         '<(skia_src_path)/utils/win/SkWGL_win.cpp',
 
         #testing
         '<(skia_src_path)/fonts/SkGScalerContext.cpp',
         '<(skia_src_path)/fonts/SkGScalerContext.h',
         '<(skia_src_path)/fonts/SkTestScalerContext.cpp',
         '<(skia_src_path)/fonts/SkTestScalerContext.h',
     ],
 }