From fac964ac0dc723cd8efd1a89604acac861671579 Mon Sep 17 00:00:00 2001
From: Charles Kerr <charles@charleskerr.com>
Date: Wed, 10 Jan 2024 14:01:49 -0600
Subject: [PATCH] refactor: migrate deprecated LazyInstance code to
 NoDestructor (#40927)

* refactor: do not use deprecated NoDestructor in javascript_environment.cc

* refactor: do not use deprecated NoDestructor in window_list.cc
---
 shell/browser/javascript_environment.cc | 16 +++++++++++-----
 shell/browser/window_list.cc            | 23 +++++++++++++----------
 shell/browser/window_list.h             | 10 ++++------
 3 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/shell/browser/javascript_environment.cc b/shell/browser/javascript_environment.cc
index cd8b0c9df809..6efd69abc33b 100644
--- a/shell/browser/javascript_environment.cc
+++ b/shell/browser/javascript_environment.cc
@@ -14,6 +14,7 @@
 #include "base/bits.h"
 #include "base/command_line.h"
 #include "base/feature_list.h"
+#include "base/no_destructor.h"
 #include "base/task/current_thread.h"
 #include "base/task/single_thread_task_runner.h"
 #include "base/task/thread_pool/initialization_util.h"
@@ -184,9 +185,6 @@ class EnabledStateObserverImpl final
   std::unordered_set<v8::TracingController::TraceStateObserver*> observers_;
 };
 
-base::LazyInstance<EnabledStateObserverImpl>::Leaky g_trace_state_dispatcher =
-    LAZY_INSTANCE_INITIALIZER;
-
 class TracingControllerImpl : public node::tracing::TracingController {
  public:
   TracingControllerImpl() = default;
@@ -265,11 +263,19 @@ class TracingControllerImpl : public node::tracing::TracingController {
     TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(category_enabled_flag, name,
                                                 traceEventHandle);
   }
+
   void AddTraceStateObserver(TraceStateObserver* observer) override {
-    g_trace_state_dispatcher.Get().AddObserver(observer);
+    GetObserverDelegate().AddObserver(observer);
   }
+
   void RemoveTraceStateObserver(TraceStateObserver* observer) override {
-    g_trace_state_dispatcher.Get().RemoveObserver(observer);
+    GetObserverDelegate().RemoveObserver(observer);
+  }
+
+ private:
+  static EnabledStateObserverImpl& GetObserverDelegate() {
+    static base::NoDestructor<EnabledStateObserverImpl> instance;
+    return *instance;
   }
 };
 
diff --git a/shell/browser/window_list.cc b/shell/browser/window_list.cc
index a2555e5a111e..78378f3aa9ad 100644
--- a/shell/browser/window_list.cc
+++ b/shell/browser/window_list.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 
 #include "base/logging.h"
+#include "base/no_destructor.h"
 #include "shell/browser/native_window.h"
 #include "shell/browser/window_list_observer.h"
 
@@ -24,10 +25,6 @@ std::vector<base::WeakPtr<T>> ConvertToWeakPtrVector(std::vector<T*> raw_ptrs) {
 
 namespace electron {
 
-// static
-base::LazyInstance<base::ObserverList<WindowListObserver>>::Leaky
-    WindowList::observers_ = LAZY_INSTANCE_INITIALIZER;
-
 // static
 WindowList* WindowList::instance_ = nullptr;
 
@@ -55,7 +52,7 @@ void WindowList::AddWindow(NativeWindow* window) {
   WindowVector& windows = GetInstance()->windows_;
   windows.push_back(window);
 
-  for (WindowListObserver& observer : observers_.Get())
+  for (WindowListObserver& observer : GetObservers())
     observer.OnWindowAdded(window);
 }
 
@@ -65,29 +62,29 @@ void WindowList::RemoveWindow(NativeWindow* window) {
   windows.erase(std::remove(windows.begin(), windows.end(), window),
                 windows.end());
 
-  for (WindowListObserver& observer : observers_.Get())
+  for (WindowListObserver& observer : GetObservers())
     observer.OnWindowRemoved(window);
 
   if (windows.empty()) {
-    for (WindowListObserver& observer : observers_.Get())
+    for (WindowListObserver& observer : GetObservers())
       observer.OnWindowAllClosed();
   }
 }
 
 // static
 void WindowList::WindowCloseCancelled(NativeWindow* window) {
-  for (WindowListObserver& observer : observers_.Get())
+  for (WindowListObserver& observer : GetObservers())
     observer.OnWindowCloseCancelled(window);
 }
 
 // static
 void WindowList::AddObserver(WindowListObserver* observer) {
-  observers_.Get().AddObserver(observer);
+  GetObservers().AddObserver(observer);
 }
 
 // static
 void WindowList::RemoveObserver(WindowListObserver* observer) {
-  observers_.Get().RemoveObserver(observer);
+  GetObservers().RemoveObserver(observer);
 }
 
 // static
@@ -118,4 +115,10 @@ WindowList::WindowList() = default;
 
 WindowList::~WindowList() = default;
 
+// static
+base::ObserverList<WindowListObserver>& WindowList::GetObservers() {
+  static base::NoDestructor<base::ObserverList<WindowListObserver>> instance;
+  return *instance;
+}
+
 }  // namespace electron
diff --git a/shell/browser/window_list.h b/shell/browser/window_list.h
index 7d8dd942f416..85d7b7d8ed92 100644
--- a/shell/browser/window_list.h
+++ b/shell/browser/window_list.h
@@ -7,7 +7,6 @@
 
 #include <vector>
 
-#include "base/lazy_instance.h"
 #include "base/observer_list.h"
 
 namespace electron {
@@ -49,13 +48,12 @@ class WindowList {
   WindowList();
   ~WindowList();
 
-  // A vector of the windows in this list, in the order they were added.
-  WindowVector windows_;
-
   // A list of observers which will be notified of every window addition and
   // removal across all WindowLists.
-  static base::LazyInstance<base::ObserverList<WindowListObserver>>::Leaky
-      observers_;
+  [[nodiscard]] static base::ObserverList<WindowListObserver>& GetObservers();
+
+  // A vector of the windows in this list, in the order they were added.
+  WindowVector windows_;
 
   static WindowList* instance_;
 };