Reland fix for thumbnail generation.

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 ef38d30fe02023e6eb3672bc58cb8dc7d416bfe9..1a914fe5bc258a8694ea009d9007df3c7c32b2cf 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac.mm
@@ -892,7 +892,7 @@ void RenderWidgetHostViewMac::WasOccluded() {
   // occur in this specific order. However, because thumbnail generation is
   // asychronous, that operation won't run before SuspendBrowserCompositorView()
   // completes. As a result you won't get a thumbnail for the page unless you
-  // happen to switch back to it. See http://crbug.com/530707 .
+  // execute these two statements in this specific order.
   render_widget_host_->WasHidden();
   SuspendBrowserCompositorView();
 }