Skip screen update when the WebView isn't ready to paint.

chrome/renderer/render_widget.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/render_widget.h"
 
 #include "app/surface/transport_dib.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/histogram.h"
@@ skipping 570 matching lines @@
   if (webwidget_->isAcceleratedCompositingActive()) {
     // Drop invalidates on the floor when we are in compositing mode.
     // TODO(nduca): Stop WebViewImpl from sending invalidates in the first
     // place.
     if (!(rect.x == 0 && rect.y == 0 &&
           rect.width == 1 && rect.height == 1)) {
       return;
     }
   }
 
+  // Painting a not-yet-ready page would cause flicker with white blank.
+  // So InvalidateRect() and PostTask() should be skipped.
+  // Because we expect at least one update after loading the page and
+  // InvalidateRect() without PostTask() can miss it,
+  // We skip both instead of skip only PostTask().
+  if (!IsReadyToPaint())
+    return;
+
   // We only want one pending DoDeferredUpdate call at any time...
   bool update_pending = paint_aggregator_.HasPendingUpdate();
 
   // The invalidated rect might be outside the bounds of the view.
   gfx::Rect view_rect(size_);
   gfx::Rect damaged_rect = view_rect.Intersect(rect);
   if (damaged_rect.IsEmpty())
     return;
 
   paint_aggregator_.InvalidateRect(damaged_rect);
@@ skipping 389 matching lines @@
 
 void RenderWidget::CleanupWindowInPluginMoves(gfx::PluginWindowHandle window) {
   for (WebPluginGeometryVector::iterator i = plugin_window_moves_.begin();
        i != plugin_window_moves_.end(); ++i) {
     if (i->window == window) {
       plugin_window_moves_.erase(i);
       break;
     }
   }
 }