Set compositor and CALayer background color from frames

content/browser/renderer_host/render_widget_host_view_mac.mm

Index: content/browser/renderer_host/render_widget_host_view_mac.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac.mm b/content/browser/renderer_host/render_widget_host_view_mac.mm
index 6266020394b9c38dc5f81004bb00d63d139d0dad..0cb516b4f5c9fab8f0112a633e9211407d9c6a6d 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -1431,6 +1431,10 @@ new BrowserCompositorMac(this, this, render_widget_host_->is_hidden(),
     cc::CompositorFrame frame) {
   TRACE_EVENT0("browser", "RenderWidgetHostViewMac::OnSwapCompositorFrame");
 
+  // Override the compositor background color. See RenderWidgetHostViewAura
+  // for more details.
+  SetBackgroundColor(frame.metadata.root_background_color);
+
   last_scroll_offset_ = frame.metadata.root_scroll_offset;
 
   page_at_minimum_scale_ =