Force include test to run on every compile.

gyp/tools.gyp

Index: gyp/tools.gyp
diff --git a/gyp/tools.gyp b/gyp/tools.gyp
index 49e441b9e237ba0c63064216437f4d243b55d495..7bf8f7f78660f6ce1ed2366102a5171cd5fd0f22 100644
--- a/gyp/tools.gyp
+++ b/gyp/tools.gyp
@@ -466,10 +466,12 @@
           '<(skia_include_path)/views/SkWindow.h',
           '<(skia_include_path)/gpu/vk',
         ],
+        'output_file' : [
+          '<(INTERMEDIATE_DIR)/test_public_includes.cpp',
+        ],
       },
       'include_dirs': [
         '<@(includes_to_test)',
-        '../src/core',
       ],
       'sources': [
         # unused_param_test.cpp is generated by the action below.
@@ -481,15 +483,16 @@
           'inputs': [
             '../tools/generate_includes_cpp.py',
             '<@(includes_to_test)',
-            # This causes the gyp generator on mac to fail
-            #'<@(paths_to_ignore)',
           ],
           'outputs': [
-            '<(INTERMEDIATE_DIR)/test_public_includes.cpp',
+            '<@(output_file)',
+            # Force the script to always run so that we pick up when files have
+            # been deleted.
+            'filename_that_does_not_exists_but_forces_rebuild.txt',
           ],
           'action': ['python', '../tools/generate_includes_cpp.py',
                                '--ignore', '<(paths_to_ignore)',
-                               '<@(_outputs)', '<@(includes_to_test)'],
+                               '<@(output_file)', '<@(includes_to_test)'],
         },
       ],
     },