Handle construction/destruction of GObject private data containing C++ objects in Linux embedder tests (#50022)

See https://github.com/flutter/flutter/issues/140183
https://dart.googlesource.com/external/github.com/flutter/engine/+/7ac56663707d56ddfef2ebc7d6b7055cb53a7747

DEPS

diff --git a/DEPS b/DEPS
index 38c4828..ce94925 100644
--- a/DEPS
+++ b/DEPS
@@ -277,7 +277,7 @@
 deps = {
   'engine/src': 'https://github.com/flutter/buildroot.git' + '@' + '5d969bd98e31ec90c23ccb982666ace80559f442',
 
-  'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + 'cca222bcf827e70263f9caeb8f00f6d86d042159',
+  'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + '7ac56663707d56ddfef2ebc7d6b7055cb53a7747',
 
   'engine/src/third_party/dart': Var('dart_git') + '/sdk' + '@' + '67dc465e8799b0e3ba5b496848e9c15a623155b7',
 

commits.json

diff --git a/commits.json b/commits.json
index 9c91cbc..a98b305 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
-  "engine/src/flutter":"cca222bcf827e70263f9caeb8f00f6d86d042159",
+  "engine/src/flutter":"7ac56663707d56ddfef2ebc7d6b7055cb53a7747",
   "engine/src/third_party/dart":"67dc465e8799b0e3ba5b496848e9c15a623155b7",
   "flutter":"21ca59e72c57ec1e0078a280221e0b44b0e9ad89"
 }
\ No newline at end of file