Tidy DEFINE_(THREAD_SAFE_)STATIC_LOCAL() implementations.

third_party/WebKit/Source/core/loader/EmptyClients.cpp

Index: third_party/WebKit/Source/core/loader/EmptyClients.cpp
diff --git a/third_party/WebKit/Source/core/loader/EmptyClients.cpp b/third_party/WebKit/Source/core/loader/EmptyClients.cpp
index b3bd6352f92845bef4ef3f138eafb83e0f2fe933..a5df28b9e48a0def0c235352e5e9a1740c2b8700 100644
--- a/third_party/WebKit/Source/core/loader/EmptyClients.cpp
+++ b/third_party/WebKit/Source/core/loader/EmptyClients.cpp
@@ -47,8 +47,12 @@
 namespace blink {
 
 void fillWithEmptyClients(Page::PageClients& pageClients) {
+  // |ChromeClient| contains a weak reference to a |Node| (which derives
+  // from |ScriptWrappable|). That reference is only used for unit testing
+  // purposes and will not accidentally leak between contexts. Consequently,
+  // disable the singleton verification check.
   DEFINE_STATIC_LOCAL(ChromeClient, dummyChromeClient,
-                      (EmptyChromeClient::create()));
+                      (EmptyChromeClient::create()), CheckScriptWrappable::No);
   pageClients.chromeClient = &dummyChromeClient;
 
   DEFINE_STATIC_LOCAL(EmptyContextMenuClient, dummyContextMenuClient, ());