Revert of Have DM manually encode its .png outputs.

gyp/dm.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.
 # GYP for "dm" (Diamond Master, a.k.a Dungeon master, a.k.a GM 2).
 {
   'include_dirs': [
     '../dm',
     '../gm',
     '../include/private',
     '../src/core',
     '../src/effects',
     '../src/images',
     '../src/lazy',
     '../src/pipe/utils/',
     '../src/utils',
     '../src/utils/debugger',
     '../tests',
     '../tools',
   ],
   'dependencies': [
     'etc1.gyp:libetc1',
     'flags.gyp:flags',
     'jsoncpp.gyp:jsoncpp',
-    'libpng.gyp:libpng_static',
     'skia_lib.gyp:skia_lib',
     'svg.gyp:svg',
     'tools.gyp:crash_handler',
     'tools.gyp:proc_stats',
     'tools.gyp:sk_tool_utils',
     'tools.gyp:timer',
     'xml.gyp:xml',
     'xps.gyp:xps',
   ],
   'includes': [
@@ skipping 11 matching lines @@
     '../src/utils/debugger/SkDebugCanvas.cpp',
     '../src/utils/debugger/SkDrawCommand.cpp',
     '../src/utils/debugger/SkObjectParser.cpp',
   ],
   'conditions': [
     [ 'skia_gpu == 1', {
       'dependencies': [ 'gputest.gyp:skgputest' ],
     }],
   ],
 }