gpu: Add flag for enabling asynchronous worker context.

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 13ff4c9fbaa193c7d827989be89d6963410714ae..0298f3f51e04ae2d9621291ae5c49e5c89da57ec 100644
--- a/content/renderer/gpu/render_widget_compositor.cc
+++ b/content/renderer/gpu/render_widget_compositor.cc
@@ -293,6 +293,8 @@ void RenderWidgetCompositor::Initialize(float device_scale_factor) {
       compositor_deps_->IsGpuRasterizationForced();
   settings.gpu_rasterization_enabled =
       compositor_deps_->IsGpuRasterizationEnabled();
+  settings.async_worker_context_enabled =
+      compositor_deps_->IsAsyncWorkerContextEnabled();
 
   settings.can_use_lcd_text = compositor_deps_->IsLcdTextEnabled();
   settings.use_distance_field_text =