Use hide_scrollbars setting for Android WebView.

content/renderer/gpu/render_widget_compositor.cc

Index: content/renderer/gpu/render_widget_compositor.cc
diff --git a/content/renderer/gpu/render_widget_compositor.cc b/content/renderer/gpu/render_widget_compositor.cc
index 6aa7fb914092517a46352dc1212c871307dfa851..a2441f236a941d23ab1136a71d08f28c50f01137 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -384,17 +384,11 @@ cc::LayerTreeSettings RenderWidgetCompositor::GenerateLayerTreeSettings(
   if (base::SysInfo::IsLowEndDevice())
     settings.gpu_rasterization_enabled = false;
   settings.using_synchronous_renderer_compositor = using_synchronous_compositor;
-  if (using_synchronous_compositor) {
-    // Android WebView uses system scrollbars, so make ours invisible.
-    settings.scrollbar_animator = cc::LayerTreeSettings::NO_ANIMATOR;
-    settings.solid_color_scrollbar_color = SK_ColorTRANSPARENT;
-  } else {
-    settings.scrollbar_animator = cc::LayerTreeSettings::LINEAR_FADE;
-    settings.scrollbar_fade_delay_ms = 300;
-    settings.scrollbar_fade_resize_delay_ms = 2000;
-    settings.scrollbar_fade_duration_ms = 300;
-    settings.solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
-  }
+  settings.scrollbar_animator = cc::LayerTreeSettings::LINEAR_FADE;
+  settings.scrollbar_fade_delay_ms = 300;
+  settings.scrollbar_fade_resize_delay_ms = 2000;
+  settings.scrollbar_fade_duration_ms = 300;
+  settings.solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
   settings.renderer_settings.highp_threshold_min = 2048;
   // Android WebView handles root layer flings itself.
   settings.ignore_root_layer_flings = using_synchronous_compositor;