Destroy all Singletons and LazyInstances between each test.

base/test/test_suite.h

 // 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.
 
 #ifndef BASE_TEST_TEST_SUITE_H_
 #define BASE_TEST_TEST_SUITE_H_
 
 // Defines a basic test suite framework for running gtest based tests.  You can
 // instantiate this class in your main function and call its Run method to run
 // any gtest based tests that are linked into your executable.
@@ skipping 41 matching lines @@
 
   // Disable crash dialogs so that it doesn't gum up the buildbot
   virtual void SuppressErrorDialogs();
 
   // Override these for custom initialization and shutdown handling.  Use these
   // instead of putting complex code in your constructor/destructor.
 
   virtual void Initialize();
   virtual void Shutdown();
 
+  // Sets up a TestEventListener to shadow the at_exit_manager_ between each
+  // individual test. Broken test suites can override this method to disable
+  // this behavior until they can be fixed.
+  virtual void EnableSingletonTestIsolation();

[jam, 2013/05/07 18:09:57]

i highly suggest not adding this method, i.e. not having a way for tests to get
out of this correct mode.

when we add things like ScopedAllowIO, they  just get misused

[Robert Sesek, 2013/05/07 18:12:29]

Good point. Done.

+
   // Make sure that we setup an AtExitManager so Singleton objects will be
   // destroyed.
   scoped_ptr<base::AtExitManager> at_exit_manager_;
 
  private:
   // Basic initialization for the test suite happens here.
   void PreInitialize(int argc, char** argv, bool create_at_exit_manager);
 
   bool initialized_command_line_;
 
   DISALLOW_COPY_AND_ASSIGN(TestSuite);
 };
 
 }  // namespace base
 
 // TODO(brettw) remove this. This is a temporary hack to allow WebKit to compile
 // until we can update it to use "base::" (preventing a two-sided patch).
 using base::TestSuite;
 
 #endif  // BASE_TEST_TEST_SUITE_H_