Revert "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 584eb9b95e73114a6bd8ca300342bff1cf3324e5..14a008f1708c0df68e99836456aa25812d1ed9e0 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -403,12 +403,21 @@ cc::LayerTreeSettings RenderWidgetCompositor::GenerateLayerTreeSettings(
   if (base::SysInfo::IsLowEndDevice())
     settings.gpu_rasterization_enabled = false;
   settings.using_synchronous_renderer_compositor = using_synchronous_compositor;
-  settings.scrollbar_animator = cc::LayerTreeSettings::LINEAR_FADE;
-  settings.scrollbar_fade_delay = base::TimeDelta::FromMilliseconds(300);
-  settings.scrollbar_fade_resize_delay =
-      base::TimeDelta::FromMilliseconds(2000);
-  settings.scrollbar_fade_duration = base::TimeDelta::FromMilliseconds(300);
-  settings.solid_color_scrollbar_color = SkColorSetARGB(128, 128, 128, 128);
+  if (using_synchronous_compositor) {
+    // Android WebView uses system scrollbars, so make ours invisible.
+    // http://crbug.com/677348: This can't be done using hide_scrollbars
+    // setting because supporting -webkit custom scrollbars is still desired
+    // on sublayers.
+    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 = base::TimeDelta::FromMilliseconds(300);
+    settings.scrollbar_fade_resize_delay =
+        base::TimeDelta::FromMilliseconds(2000);
+    settings.scrollbar_fade_duration = base::TimeDelta::FromMilliseconds(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;