Have the unload event execute in background on cross-site navigations

chrome/browser/renderer_host/web_cache_manager_browsertest.cc

 // Copyright (c) 2012 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 <string>
 
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/renderer_host/web_cache_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_commands.h"
@@ skipping 39 matching lines @@
 
   browser()->tab_strip_model()->ActivateTabAt(0, true);
   chrome::CloseTab(browser());
   browser()->tab_strip_model()->ActivateTabAt(0, true);
   chrome::CloseTab(browser());
   browser()->tab_strip_model()->ActivateTabAt(0, true);
   chrome::CloseTab(browser());
 
   ui_test_utils::NavigateToURL(browser(), url);
 
-  EXPECT_EQ(
-      WebCacheManager::GetInstance()->active_renderers_.size(), 1U);
+  // Depending on the speed of execution of the unload event, we may have one or
+  // two active renderers at that point (one executing the unload event in
+  // background).
+  EXPECT_GE(WebCacheManager::GetInstance()->active_renderers_.size(), 1U);
+  EXPECT_LE(WebCacheManager::GetInstance()->active_renderers_.size(), 2U);
   EXPECT_EQ(
       WebCacheManager::GetInstance()->inactive_renderers_.size(), 0U);
-  EXPECT_EQ(
-      WebCacheManager::GetInstance()->stats_.size(), 1U);
+  EXPECT_GE(WebCacheManager::GetInstance()->stats_.size(), 1U);
+  EXPECT_LE(WebCacheManager::GetInstance()->stats_.size(), 2U);
 }