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

extensions/browser/extension_function_registry.cc

Index: extensions/browser/extension_function_registry.cc
diff --git a/extensions/browser/extension_function_registry.cc b/extensions/browser/extension_function_registry.cc
index 1e1640a4c4d813d57efda997280298b3a94bf316..e6281c3e0ae5089054807a29612d3a48a57e79f2 100644
--- a/extensions/browser/extension_function_registry.cc
+++ b/extensions/browser/extension_function_registry.cc
@@ -46,7 +46,7 @@ ExtensionFunction* ExtensionFunctionRegistry::NewFunction(
     const std::string& name) {
   FactoryMap::iterator iter = factories_.find(name);
   if (iter == factories_.end()) {
-    return NULL;
+    return nullptr;
   }
   ExtensionFunction* function = iter->second.factory_();
   function->set_name(name);
@@ -55,7 +55,8 @@ ExtensionFunction* ExtensionFunctionRegistry::NewFunction(
 }
 
 ExtensionFunctionRegistry::FactoryEntry::FactoryEntry()
-    : factory_(0), histogram_value_(extensions::functions::UNKNOWN) {}
+    : factory_(nullptr), histogram_value_(extensions::functions::UNKNOWN) {
+}
 
 ExtensionFunctionRegistry::FactoryEntry::FactoryEntry(
     ExtensionFunctionFactory factory,