Convert the overlay scrollbar flag to use FeatureList

third_party/WebKit/LayoutTests/VirtualTestSuites

Index: third_party/WebKit/LayoutTests/VirtualTestSuites
diff --git a/third_party/WebKit/LayoutTests/VirtualTestSuites b/third_party/WebKit/LayoutTests/VirtualTestSuites
index 2375ea98348a2922dfca5b0c483a6808ce987230..8510e5335fa0443ecd13d75355b55a621d34a214 100644
--- a/third_party/WebKit/LayoutTests/VirtualTestSuites
+++ b/third_party/WebKit/LayoutTests/VirtualTestSuites
@@ -126,10 +126,10 @@
   {
     "prefix": "android",
     "base": "fullscreen",
-    "args": ["--enable-threaded-compositing",
+    "args": ["--enable-features=OverlayScrollbar", "--enable-threaded-compositing",
              "--enable-fixed-position-compositing", "--enable-prefer-compositing-to-lcd-text",
              "--enable-composited-scrolling-for-frames", "--enable-gesture-tap-highlight", "--enable-pinch",
-             "--force-overlay-fullscreen-video", "--enable-overlay-scrollbars", "--enable-overscroll-notifications",
+             "--force-overlay-fullscreen-video", "--enable-overscroll-notifications",
              "--enable-fixed-layout", "--enable-viewport", "--disable-canvas-aa",
              "--disable-composited-antialiasing"]
   },