Disallow static locals of ScriptWrappable-derived objects.

third_party/WebKit/Source/wtf/StdLibExtras.h

Index: third_party/WebKit/Source/wtf/StdLibExtras.h
diff --git a/third_party/WebKit/Source/wtf/StdLibExtras.h b/third_party/WebKit/Source/wtf/StdLibExtras.h
index 26ba1d8d02958298aacfc73daea5743ccbbce201..3ceeffbfaf57129164c618c89d9e769f31bb77b4 100644
--- a/third_party/WebKit/Source/wtf/StdLibExtras.h
+++ b/third_party/WebKit/Source/wtf/StdLibExtras.h
@@ -63,6 +63,8 @@ class WTF_EXPORT StaticLocalVerifier {
 namespace blink {
 template <typename T>
 class Persistent;
+
+class ScriptWrappable;
 };
 
 template <typename T,
@@ -112,12 +114,19 @@ class StaticLocalWrapper<T, true> {
 // LEAK_SANITIZER_REGISTER_STATIC_LOCAL() use, it taking care of the grungy
 // details.
 //
-#define DEFINE_STATIC_LOCAL(Type, Name, Arguments)                   \
-  DEFINE_STATIC_LOCAL_CHECK_THREADSAFE_ACCESS(Name);                 \
-  using WrappedTypeFor##Name = StaticLocalWrapper<Type>::WrapType;   \
-  static WrappedTypeFor##Name* WrappedInstanceFor##Name =            \
-      LEAK_SANITIZER_REGISTER_STATIC_LOCAL(                          \
-          WrappedTypeFor##Name, new WrappedTypeFor##Name Arguments); \
+#define DEFINE_STATIC_LOCAL(Type, Name, Arguments)                       \
+  DEFINE_STATIC_LOCAL_CHECK_THREADSAFE_ACCESS(Name);                     \
+  using WrappedTypeFor##Name = StaticLocalWrapper<Type>::WrapType;       \
+  static_assert(                                                         \
+      !WTF::IsPersistentReferenceType<WrappedTypeFor##Name>::value ||    \
+          !WTF::IsSubclass<WTF::RemoveTemplate<WrappedTypeFor##Name,     \
+                                               blink::Persistent>::type, \
+                           blink::ScriptWrappable>::value,               \
+      "It is unsafe to keep a static local singleton to a "              \
+      "ScriptWrappable-derived object");                                 \
+  static WrappedTypeFor##Name* WrappedInstanceFor##Name =                \
+      LEAK_SANITIZER_REGISTER_STATIC_LOCAL(                              \
+          WrappedTypeFor##Name, new WrappedTypeFor##Name Arguments);     \
   Type& Name = StaticLocalWrapper<Type>::unwrap(WrappedInstanceFor##Name);
 
 // Use this to declare and define a static local pointer to a ref-counted object