Omnibox - ClipboardRecentContent - Make Proper Singleton

components/open_from_clipboard/clipboard_recent_content.cc

Index: components/open_from_clipboard/clipboard_recent_content.cc
diff --git a/components/open_from_clipboard/clipboard_recent_content.cc b/components/open_from_clipboard/clipboard_recent_content.cc
index a31a9d6f76aca9e1c9d9246573a3d54aecedde26..ca18421b44fb8d7c4f03fc9554d3bacfab8e19fc 100644
--- a/components/open_from_clipboard/clipboard_recent_content.cc
+++ b/components/open_from_clipboard/clipboard_recent_content.cc
@@ -24,7 +24,6 @@ const char* kAuthorizedSchemes[] = {
 ClipboardRecentContent::ClipboardRecentContent() {}
 
 ClipboardRecentContent::~ClipboardRecentContent() {
-  g_clipboard_recent_content = nullptr;
 }
 
 // static
@@ -34,6 +33,7 @@ ClipboardRecentContent* ClipboardRecentContent::GetInstance() {
 
 // static
 void ClipboardRecentContent::SetInstance(ClipboardRecentContent* instance) {
+  DCHECK(g_clipboard_recent_content == nullptr);
   g_clipboard_recent_content = instance;
 }