Get Mac viewer working with SDL

gyp/viewer.gyp

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 # GYP file to build performance testbench.
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
@@ skipping 14 matching lines @@
         '../src/gpu',
         '../src/image',
         '../src/images',
         '../src/pathops',
         '../src/views/unix',
         '../tools/timer',
       ],
       'sources': [
         '../gm/gm.cpp',
         '<!@(python find.py "*.cpp" ../tools/viewer)',
+        '<!@(python find.py "*.h" ../tools/viewer)',
 
         # views (subset of files for the Android build)
         '../src/views/SkEvent.cpp',
         '../src/views/SkEventSink.cpp',
         '../src/views/SkOSMenu.cpp',
         '../src/views/SkTagList.cpp',
         '../src/views/SkTagList.h',
         '../src/views/SkTouchGesture.cpp',
         '../src/views/SkView.cpp',
         '../src/views/SkViewPriv.cpp',
@@ skipping 33 matching lines @@
             ],
           },
         }],
         [ 'skia_os == "linux" and skia_vulkan == 1', {
           'link_settings': {
             'libraries': [
               '-lX11-xcb',
             ],
           },
         }],
+        [ 'skia_os == "mac"', {
+          'dependencies': [
+            'sdl.gyp:sdl',
+          ],
+        }],
         ['skia_os != "android"', {
           'sources/': [
             ['exclude', '_android.(h|cpp)$'],
             ['exclude', 'src/views'],
           ],
         }],
         ['skia_os != "linux"', {
           'sources/': [
             ['exclude', '_unix.(h|cpp)$'],
             ['exclude', 'keysym2ucs.c'],
           ],
         }],
         ['skia_os != "win"', {
           'sources/': [ ['exclude', '_win.(h|cpp)$'],
           ],
         }],
         ['skia_os != "mac"', {
           'sources/': [ ['exclude', '_mac.(h|cpp)$'],
           ],
         }],
         ['skia_vulkan == 0', {
           'sources/': [ ['exclude', 'Vulkan']
           ],
         }],
       ],
     },
   ],
 }