Make the gyp files more cross-platform across the Unices

ui/gfx/surface/surface.gyp

Index: ui/gfx/surface/surface.gyp
diff --git a/ui/gfx/surface/surface.gyp b/ui/gfx/surface/surface.gyp
index 0cbfe94024185f1ccc0e3e2eccf437f0c6cfa9c2..c054df0b21825a6ac6fe5a58306a26bbeb29e4b7 100644
--- a/ui/gfx/surface/surface.gyp
+++ b/ui/gfx/surface/surface.gyp
@@ -10,11 +10,13 @@
       ['exclude', '/(gtk|win|x11)_[^/]*\\.cc$'],
     ],
     'conditions': [
-      ['OS=="linux" or OS=="freebsd" or OS=="openbsd"', {'sources/': [
-        ['include', '/gtk/'],
-        ['include', '_(gtk|linux|posix|skia|x)\\.cc$'],
-        ['include', '/(gtk|x11)_[^/]*\\.cc$'],
-      ]}],
+      ['toolkit_uses_gtk==1', {
+        'sources/': [
+          ['include', '/gtk/'],
+          ['include', '_(gtk|linux|posix|skia|x)\\.cc$'],
+          ['include', '/(gtk|x11)_[^/]*\\.cc$'],
+        ],
+      }],
       ['OS=="mac"', {'sources/': [
         ['include', '/cocoa/'],
         ['include', '_(cocoa|mac|posix)\\.(cc|mm?)$'],