Fixes for -Wunused-function on Linux, Android and ChromeOS

ui/snapshot/test/run_all_unittests.cc

 // Copyright (c) 2013 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 "base/bind.h"
 #include "base/test/launcher/unit_test_launcher.h"
 #include "base/test/test_suite.h"
 #include "ui/compositor/test/test_suite.h"
 
 namespace {
 
+#if !defined(USE_AURA)
 class NoAtExitBaseTestSuite : public base::TestSuite {
  public:
   NoAtExitBaseTestSuite(int argc, char** argv)
       : base::TestSuite(argc, argv, false) {
   }
 };
 
 int RunTestSuite(int argc, char** argv) {
   return NoAtExitBaseTestSuite(argc, argv).Run();
 }
+#endif  // !defined(USE_AURA)
 
 }  // namespace
 
 int main(int argc, char** argv) {
 #if defined(USE_AURA)
   ui::test::CompositorTestSuite test_suite(argc, argv);
 
   return base::LaunchUnitTests(
       argc, argv, base::Bind(&ui::test::CompositorTestSuite::Run,
                              base::Unretained(&test_suite)));
 #else
+
 #if !defined(OS_ANDROID)
   base::AtExitManager at_exit;
 #endif
   return base::LaunchUnitTests(argc,
                                argv,
                                base::Bind(&RunTestSuite, argc, argv));
 #endif
 }