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

content/renderer/gpu/render_widget_compositor.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/gpu/render_widget_compositor.h"
 
 #include <limits>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 215 matching lines @@
 
   settings.renderer_settings.disable_gpu_vsync =
       cmd->HasSwitch(switches::kDisableGpuVsync);
   settings.main_frame_before_activation_enabled =
       cmd->HasSwitch(cc::switches::kEnableMainFrameBeforeActivation) &&
       !cmd->HasSwitch(cc::switches::kDisableMainFrameBeforeActivation);
   settings.report_overscroll_only_for_scrollable_axes =
       !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);
   }
 
   settings.default_tile_size = CalculateDefaultTileSize(widget_);
   if (cmd->HasSwitch(switches::kDefaultTileWidth)) {
     int tile_width = 0;
     GetSwitchValueAsInt(*cmd,
                         switches::kDefaultTileWidth,
@@ skipping 753 matching lines @@
     return;
   provider->ContextGL()->RateLimitOffscreenContextCHROMIUM();
 }
 
 void RenderWidgetCompositor::SetSurfaceIdNamespace(
     uint32_t surface_id_namespace) {
   layer_tree_host_->set_surface_id_namespace(surface_id_namespace);
 }
 
 }  // namespace content