[SP] Enable Slimming Paint by default in Chromium and Blink.

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 0b50b6788fd0c7447299ebc92818e68cf7bb2edc..f3b6fa92025a886de1fac71cb84ba41b80ad9bdd 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -233,7 +233,8 @@ void RenderWidgetCompositor::Initialize() {
       !compositor_deps_->IsElasticOverscrollEnabled();
   settings.accelerated_animation_enabled =
       !cmd->HasSwitch(cc::switches::kDisableThreadedAnimation);
-  settings.use_display_lists = cmd->HasSwitch(switches::kEnableSlimmingPaint);
+  settings.use_display_lists = cmd->HasSwitch(switches::kEnableSlimmingPaint) ||
+      !cmd->HasSwitch(switches::kDisableSlimmingPaint);
   if (cmd->HasSwitch(switches::kEnableCompositorAnimationTimelines)) {
     settings.use_compositor_animation_timelines = true;
     blink::WebRuntimeFeatures::enableCompositorAnimationTimelines(true);