Turn on the fixed position stacking context flag by default

content/public/common/content_switches.cc

Index: content/public/common/content_switches.cc
diff --git a/content/public/common/content_switches.cc b/content/public/common/content_switches.cc
index 6dc97dde54ec5e7c8f5eaaec9c0900bf2a43239b..ae311bb4b815b2466da6955a8cc79658e35faec2 100644
--- a/content/public/common/content_switches.cc
+++ b/content/public/common/content_switches.cc
@@ -675,6 +675,9 @@ const char kDefaultTileHeight[]             = "default-tile-height";
 const char kMaxUntiledLayerWidth[]          = "max-untiled-layer-width";
 const char kMaxUntiledLayerHeight[]         = "max-untiled-layer-height";
 
-const char kFixedPositionCreatesStackingContext[]
-    = "fixed-position-creates-stacking-context";
+const char kEnableFixedPositionCreatesStackingContext[]
+    = "enable-fixed-position-creates-stacking-context";
+const char kDisableFixedPositionCreatesStackingContext[]
+    = "disable-fixed-position-creates-stacking-context";
+
 }  // namespace switches