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);
+  // We may have two renderers if one is still executing the unload event in the

[Charlie Reis, 2013/12/09 20:12:29]

Slight concern: Are we likely to have many flaky tests if we don't know when a
renderer is going to go away?

+  // background.
+  EXPECT_GT(
+      WebCacheManager::GetInstance()->active_renderers_.size(), 0U);
+  EXPECT_LT(
+      WebCacheManager::GetInstance()->active_renderers_.size(), 3U);
   EXPECT_EQ(
       WebCacheManager::GetInstance()->inactive_renderers_.size(), 0U);
-  EXPECT_EQ(
-      WebCacheManager::GetInstance()->stats_.size(), 1U);
+  EXPECT_GT(
+      WebCacheManager::GetInstance()->stats_.size(), 0U);
+  EXPECT_LT(
+      WebCacheManager::GetInstance()->stats_.size(), 3U);
 }