service worker: Avoid starting up for activation during shutdown

base/compiler_specific.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_COMPILER_SPECIFIC_H_
 #define BASE_COMPILER_SPECIFIC_H_
 
 #include "build/build_config.h"
 
 #if defined(COMPILER_MSVC)
@@ skipping 37 matching lines @@
 // declaration (either "," or "{") has to be placed before the pop macro.
 //
 // Example usage:
 // class EXPORT_API Foo : NON_EXPORTED_BASE(public Bar) {
 //
 // MSVC Compiler warning C4275:
 // non dll-interface class 'Bar' used as base for dll-interface class 'Foo'.
 // Note that this is intended to be used only when no access to the base class'
 // static data is done through derived classes or inline methods. For more info,
 // see http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx
-#define NON_EXPORTED_BASE(code) MSVC_SUPPRESS_WARNING(4275) \
-                                code
+#define NON_EXPORTED_BASE(...) \

[nhiroki, 2016/06/01 05:51:47]

Why do we need this change?

[falken, 2016/06/01 09:20:05]

For some reason ServiceWorkerRegistration had to become RefCountedThreadSafe
after it started using the timer. It must use DeleteOnIOThread or some crashes
happen. That means it went from inheriting:
base::RefCounted<ServiceWorkerRegistration>
to:
base::RefCountedThreadSafe<ServiceWorkerRegistration,
BrowserThread::DeleteOnIOThread> 

That comma destroys the NON_EXPORTED_BASE macro since it thinks it's two
arguments.

+  MSVC_SUPPRESS_WARNING(4275)  \
+  __VA_ARGS__
 
 #else  // Not MSVC
 
 #define _Printf_format_string_
 #define MSVC_SUPPRESS_WARNING(n)
 #define MSVC_PUSH_DISABLE_WARNING(n)
 #define MSVC_PUSH_WARNING_LEVEL(n)
 #define MSVC_POP_WARNING()
 #define MSVC_DISABLE_OPTIMIZE()
 #define MSVC_ENABLE_OPTIMIZE()
-#define NON_EXPORTED_BASE(code) code
+#define NON_EXPORTED_BASE(...) __VA_ARGS__
 
 #endif  // COMPILER_MSVC
 
 
 // Annotate a variable indicating it's ok if the variable is not used.
 // (Typically used to silence a compiler warning when the assignment
 // is important for some other reason.)
 // Use like:
 //   int x = ...;
 //   ALLOW_UNUSED_LOCAL(x);
@@ skipping 108 matching lines @@
 
 // Compiler feature-detection.
 // clang.llvm.org/docs/LanguageExtensions.html#has-feature-and-has-extension
 #if defined(__has_feature)
 #define HAS_FEATURE(FEATURE) __has_feature(FEATURE)
 #else
 #define HAS_FEATURE(FEATURE) 0
 #endif
 
 #endif  // BASE_COMPILER_SPECIFIC_H_