CC Animations: Enable external animation host for 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 15dbc68df592cbe308ea4b15f9e4c4e27e484309..10e7bac5578ed6efb608071160d23bf09a4a0b29 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -249,10 +249,10 @@ void RenderWidgetCompositor::Initialize() {
   settings.accelerated_animation_enabled =
       compositor_deps_->IsThreadedAnimationEnabled();
 
-  if (cmd->HasSwitch(switches::kEnableCompositorAnimationTimelines)) {
-    settings.use_compositor_animation_timelines = true;
-    blink::WebRuntimeFeatures::enableCompositorAnimationTimelines(true);
-  }
+  settings.use_compositor_animation_timelines =
+      !cmd->HasSwitch(switches::kDisableCompositorAnimationTimelines);
+  blink::WebRuntimeFeatures::enableCompositorAnimationTimelines(
+      settings.use_compositor_animation_timelines);
 
   settings.default_tile_size = CalculateDefaultTileSize(widget_);
   if (cmd->HasSwitch(switches::kDefaultTileWidth)) {