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

extensions/browser/api/cast_channel/cast_channel_api.cc

Index: extensions/browser/api/cast_channel/cast_channel_api.cc
diff --git a/extensions/browser/api/cast_channel/cast_channel_api.cc b/extensions/browser/api/cast_channel/cast_channel_api.cc
index b21458dae3dc660227d4c46d5e0b39e8745ef68b..3732bd90ec2b67b9b64b031f1b8f4cd5552a3e69 100644
--- a/extensions/browser/api/cast_channel/cast_channel_api.cc
+++ b/extensions/browser/api/cast_channel/cast_channel_api.cc
@@ -185,7 +185,8 @@ void CastChannelAPI::OnMessage(const CastSocket* socket,
 CastChannelAPI::~CastChannelAPI() {}
 
 CastChannelAsyncApiFunction::CastChannelAsyncApiFunction()
-  : manager_(NULL), error_(cast_channel::CHANNEL_ERROR_NONE) { }
+    : manager_(nullptr), error_(cast_channel::CHANNEL_ERROR_NONE) {
+}
 
 CastChannelAsyncApiFunction::~CastChannelAsyncApiFunction() { }
 
@@ -473,7 +474,7 @@ void CastChannelCloseFunction::OnClose(int result) {
     SetResultFromSocket(*socket);
     // This will delete |socket|.
     RemoveSocket(channel_id);
-    socket = NULL;
+    socket = nullptr;
   }
   AsyncWorkCompleted();
 }