Move ExtensionWarningService and ExtensionsWarningSet to extensions.

extensions/shell/common/shell_extensions_client.cc

Index: extensions/shell/common/shell_extensions_client.cc
diff --git a/extensions/shell/common/shell_extensions_client.cc b/extensions/shell/common/shell_extensions_client.cc
index 0c5844f30a3738b2ad4de6b711a581ca21a59815..003621959515aef3051d70778b0ce8a400d2339a 100644
--- a/extensions/shell/common/shell_extensions_client.cc
+++ b/extensions/shell/common/shell_extensions_client.cc
@@ -104,6 +104,10 @@ ShellExtensionsClient::GetPermissionMessageProvider() const {
   return g_permission_message_provider.Get();
 }
 
+const std::string ShellExtensionsClient::GetProductName() {
+  return "app_shell";
+}
+
 scoped_ptr<FeatureProvider> ShellExtensionsClient::CreateFeatureProvider(
     const std::string& name) const {
   scoped_ptr<FeatureProvider> provider;