Fix for the flashing of the front tab....

chrome/browser/tabs/tab_strip_model.cc

 // Copyright (c) 2006-2008 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/browser/tabs/tab_strip_model.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/stl_util-inl.h"
@@ skipping 380 matching lines @@
 
   // Ensure that the new TabContentsView begins at the same size as the
   // previous TabContentsView if it existed.  Otherwise, the initial WebKit
   // layout will be performed based on a width of 0 pixels, causing a
   // very long, narrow, inaccurate layout.  Because some scripts on pages (as
   // well as WebKit's anchor link location calculation) are run on the
   // initial layout and not recalculated later, we need to ensure the first
   // layout is performed with sane view dimensions even when we're opening a
   // new background tab.
   if (TabContents* old_contents = GetSelectedTabContents()) {
-    if (!foreground)
+    if (!foreground) {
       contents->view()->SizeContents(old_contents->view()->GetContainerSize());
+      // We need to hide the contents or else we get and execute paints for
+      // background tabs. With enough background tabs they will steal the
+      // backing store of the visible tab causing flashing. See bug 20831.
+      contents->HideContents();

[darin (slow to review), 2009/09/04 06:25:57]

shouldn't we hide the contents before we size them?  SizeContents sends a resize
IPC to the renderer, which could kick off a paint.

why not create tabs hidden first?

+    }
   }
 }
 
 void TabStripModel::CloseSelectedTab() {
   CloseTabContentsAt(selected_index_);
 }
 
 void TabStripModel::SelectNextTab() {
   // This may happen during automated testing or if a user somehow buffers
   // many key accelerators.
@@ skipping 252 matching lines @@
   int index = GetIndexOfTabContents(contents);
   contents_data_.at(index)->opener = &opener->controller();
 }
 
 // static
 bool TabStripModel::OpenerMatches(const TabContentsData* data,
                                   const NavigationController* opener,
                                   bool use_group) {
   return data->opener == opener || (use_group && data->group == opener);
 }