Wait showing html dialog until renderer finish painting after page is loaded.

views/widget/native_widget_gtk.cc

Index: views/widget/native_widget_gtk.cc
diff --git a/views/widget/native_widget_gtk.cc b/views/widget/native_widget_gtk.cc
index e5dd8b113c2a422f958580ee301f9c02be68963e..f9175e4c0c5f3d50398f0e9359d88bbd1b01f0ae 100644
--- a/views/widget/native_widget_gtk.cc
+++ b/views/widget/native_widget_gtk.cc
@@ -279,7 +279,6 @@ static GtkWidget* CreateDragIconWidget(GdkPixbuf* drag_image) {
 
 // static
 GtkWidget* NativeWidgetGtk::null_parent_ = NULL;
-bool NativeWidgetGtk::debug_paint_enabled_ = false;
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeWidgetGtk, public:
@@ -507,7 +506,7 @@ void NativeWidgetGtk::ActiveWindowChanged(GdkWindow* active_window) {
 }
 
 ////////////////////////////////////////////////////////////////////////////////
-// NativeWidgetGtk, Widget implementation:
+// NativeWidgetGtk implementation:
 
 void NativeWidgetGtk::ClearNativeFocus() {
   DCHECK(!child_);
@@ -550,9 +549,17 @@ bool NativeWidgetGtk::HandleKeyboardEvent(const KeyEvent& key) {
   return handled;
 }
 
+bool NativeWidgetGtk::SuppressFreezeUpdates() {
+  if (!painted_) {
+    painted_ = true;
+    return true;
+  }
+  return false;
+}
+
 // static
 void NativeWidgetGtk::EnableDebugPaint() {
-  debug_paint_enabled_ = true;
+  gdk_window_set_debug_updates(true);
 }
 
 // static
@@ -1166,20 +1173,6 @@ gboolean NativeWidgetGtk::OnPaint(GtkWidget* widget, GdkEventExpose* event) {
     }
   }
 
-  if (debug_paint_enabled_) {
-    // Using cairo directly because using skia didn't have immediate effect.
-    cairo_t* cr = gdk_cairo_create(event->window);
-    gdk_cairo_region(cr, event->region);
-    cairo_set_source_rgb(cr, 1, 0, 0);  // red
-    cairo_rectangle(cr,
-                    event->area.x, event->area.y,
-                    event->area.width, event->area.height);
-    cairo_fill(cr);
-    cairo_destroy(cr);
-    // Make sure that users see the red flash.
-    XSync(ui::GetXDisplay(), false /* don't discard events */);
-  }
-
   ui::ScopedRegion region(gdk_region_copy(event->region));
   if (!gdk_region_empty(region.Get())) {
     GdkRectangle clip_bounds;