Default GR_GL_FUNCTION_TYPE to __stdcall on Windows.

gyp/gpu.gyp

Index: gyp/gpu.gyp
diff --git a/gyp/gpu.gyp b/gyp/gpu.gyp
index c17789ab7a7f3de09941a74a2a2354ebd0dcfdf2..a2909b802435c691ec99851e887fe9fdb3d3d6b3 100644
--- a/gyp/gpu.gyp
+++ b/gyp/gpu.gyp
@@ -65,13 +65,6 @@
       }],
     ],
     'direct_dependent_settings': {
-      'conditions': [
-        [ 'skia_os == "win"', {
-          'defines': [
-            'GR_GL_FUNCTION_TYPE=__stdcall',
-          ],
-        }],
-      ],
       'include_dirs': [
         '../include/gpu',
       ],
@@ -251,7 +244,7 @@
                 # the gyp -> android.mk generator doesn't seem to like cpp files
                 # in directories outside of src, bench, or dm.  Until this gets fixed
                 # I just start the path in the src directory.
-                '<(skia_src_path)/../tools/viewer/sk_app/WindowContext.cpp', 
+                '<(skia_src_path)/../tools/viewer/sk_app/WindowContext.cpp',
                 '<(skia_src_path)/../tools/viewer/sk_app/VulkanWindowContext.cpp',
                 '<(skia_src_path)/../tools/viewer/sk_app/android/VulkanWindowContext_android.cpp'
               ],