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

extensions/common/manifest_handlers/requirements_info.cc

Index: extensions/common/manifest_handlers/requirements_info.cc
diff --git a/extensions/common/manifest_handlers/requirements_info.cc b/extensions/common/manifest_handlers/requirements_info.cc
index 9a2a22b92aaf39ddfb247ecbd48aa2754b749178..8308a690d8329e5eb5ec7761b72eed7b9b2dfdeb 100644
--- a/extensions/common/manifest_handlers/requirements_info.cc
+++ b/extensions/common/manifest_handlers/requirements_info.cc
@@ -22,7 +22,7 @@ RequirementsInfo::RequirementsInfo(const Manifest* manifest)
       window_shape(false) {
   // Before parsing requirements from the manifest, automatically default the
   // NPAPI plugin requirement based on whether it includes NPAPI plugins.
-  const base::ListValue* list_value = NULL;
+  const base::ListValue* list_value = nullptr;
   npapi = manifest->GetList(keys::kPlugins, &list_value) &&
           !list_value->empty();
 }
@@ -69,7 +69,7 @@ bool RequirementsHandler::Parse(Extension* extension, base::string16* error) {
     return true;
   }
 
-  const base::DictionaryValue* requirements_value = NULL;
+  const base::DictionaryValue* requirements_value = nullptr;
   if (!extension->manifest()->GetDictionary(keys::kRequirements,
                                             &requirements_value)) {
     *error = base::ASCIIToUTF16(errors::kInvalidRequirements);
@@ -104,7 +104,7 @@ bool RequirementsHandler::Parse(Extension* extension, base::string16* error) {
         }
       }
     } else if (iter.key() == "3D") {
-      const base::ListValue* features = NULL;
+      const base::ListValue* features = nullptr;
       if (!requirement_value->GetListWithoutPathExpansion("features",
                                                           &features) ||
           !features) {