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

extensions/browser/api/extensions_api_client.cc

Index: extensions/browser/api/extensions_api_client.cc
diff --git a/extensions/browser/api/extensions_api_client.cc b/extensions/browser/api/extensions_api_client.cc
index 3f5ccbdef826111f9472ebe439eee7a75f8e6c4b..ca9172b37d6c242b1b29374c50e6c7bc58c583ea 100644
--- a/extensions/browser/api/extensions_api_client.cc
+++ b/extensions/browser/api/extensions_api_client.cc
@@ -12,12 +12,14 @@ namespace extensions {
 class AppViewGuestDelegate;
 
 namespace {
-ExtensionsAPIClient* g_instance = NULL;
+ExtensionsAPIClient* g_instance = nullptr;
 }  // namespace
 
 ExtensionsAPIClient::ExtensionsAPIClient() { g_instance = this; }
 
-ExtensionsAPIClient::~ExtensionsAPIClient() { g_instance = NULL; }
+ExtensionsAPIClient::~ExtensionsAPIClient() {
+  g_instance = nullptr;
+}
 
 // static
 ExtensionsAPIClient* ExtensionsAPIClient::Get() { return g_instance; }
@@ -29,13 +31,13 @@ void ExtensionsAPIClient::AddAdditionalValueStoreCaches(
     std::map<settings_namespace::Namespace, ValueStoreCache*>* caches) {}
 
 AppViewGuestDelegate* ExtensionsAPIClient::CreateAppViewGuestDelegate() const {
-  return NULL;
+  return nullptr;
 }
 
 ExtensionOptionsGuestDelegate*
 ExtensionsAPIClient::CreateExtensionOptionsGuestDelegate(
     ExtensionOptionsGuest* guest) const {
-  return NULL;
+  return nullptr;
 }
 
 scoped_ptr<MimeHandlerViewGuestDelegate>
@@ -46,7 +48,7 @@ ExtensionsAPIClient::CreateMimeHandlerViewGuestDelegate(
 
 WebViewGuestDelegate* ExtensionsAPIClient::CreateWebViewGuestDelegate(
     WebViewGuest* web_view_guest) const {
-  return NULL;
+  return nullptr;
 }
 
 WebViewPermissionHelperDelegate* ExtensionsAPIClient::