Run clang-modernize -use-nullptr over src/extensions/.

extensions/renderer/user_script_set_manager.cc

Index: extensions/renderer/user_script_set_manager.cc
diff --git a/extensions/renderer/user_script_set_manager.cc b/extensions/renderer/user_script_set_manager.cc
index 4379bab3e9d01a3957b9a79109b91e47604dba74..fb06dc2d6e4c59bbce6de523d84f4a550c32940a 100644
--- a/extensions/renderer/user_script_set_manager.cc
+++ b/extensions/renderer/user_script_set_manager.cc
@@ -91,7 +91,7 @@ UserScriptSet* UserScriptSetManager::GetProgrammaticScriptsByExtension(
     const ExtensionId& extension_id) {
   UserScriptSetMap::const_iterator it =
       programmatic_scripts_.find(extension_id);
-  return it != programmatic_scripts_.end() ? it->second.get() : NULL;
+  return it != programmatic_scripts_.end() ? it->second.get() : nullptr;
 }
 
 void UserScriptSetManager::OnUpdateUserScripts(
@@ -112,7 +112,7 @@ void UserScriptSetManager::OnUpdateUserScripts(
     }
   }
 
-  UserScriptSet* scripts = NULL;
+  UserScriptSet* scripts = nullptr;
   if (!extension_id.empty()) {
     // The expectation when there is an extension that "owns" this shared
     // memory region is that the |changed_extensions| is either the empty list