From f15fa56e38e0189ae1bcc558c2048ce154c2266f Mon Sep 17 00:00:00 2001
From: Calvin <clavin@users.noreply.github.com>
Date: Sat, 19 Apr 2025 11:18:03 -0600
Subject: [PATCH] refactor: reduce & remove no-op MicrotasksScope calls
 (#46681)

* fix: do not run microtasks in V8Serializer in browser process

* Remove no-op MicrotasksScope in `shell/browser/api/electron_api_auto_updater.cc`

This call was added in https://github.com/electron/electron/pull/40576 as an expansion of `gin_helper::EmitEvent`.

Since this only runs in the browser process and `bool ignore_browser_checkpoint = true` this code is a no-op.

Node should perform a microtask checkpoint if necessary in `node::MakeCallback`.

* Remove no-op MicrotasksScope in `shell/common/api/electron_bindings.cc`

This method is only called by the browser process. The containing function, `ElectronBindings::DidReceiveMemoryDump`, is only used in two places:

* `ElectronBindings::GetProcessMemoryInfo` in the same file, which has a `CHECK` that it's running in the browser process at the top.
* From `shell/browser/api/electron_api_web_contents.cc`, which is only run in the browser process.

Added a DCHECK for clarity and validation.

* Replace `gin_helper::MicrotasksScope` with `v8::MicrotasksScope` in `shell/renderer/`

The browser check is unnecessary in the renderer. Since `gin_helper::MicrotasksScope` will always act exactly like `v8::MicrotasksScope`, it's clear to just use the v8 object directly. This also brings them in line with the many other uses of `v8::MicrotasksScope` in `shell/renderer/`.
---
 shell/browser/api/electron_api_auto_updater.cc        | 4 ----
 shell/common/api/electron_bindings.cc                 | 3 +--
 shell/renderer/api/electron_api_spell_check_client.cc | 4 ++--
 shell/renderer/electron_sandboxed_renderer_client.cc  | 8 ++++----
 4 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/shell/browser/api/electron_api_auto_updater.cc b/shell/browser/api/electron_api_auto_updater.cc
index 2a1feaa9d837..4111342ec1f9 100644
--- a/shell/browser/api/electron_api_auto_updater.cc
+++ b/shell/browser/api/electron_api_auto_updater.cc
@@ -46,10 +46,6 @@ void AutoUpdater::OnError(const std::string& message) {
         gin::StringToV8(isolate, message),
     };
 
-    gin_helper::MicrotasksScope microtasks_scope{
-        wrapper->GetCreationContextChecked(), true,
-        v8::MicrotasksScope::kRunMicrotasks};
-
     node::MakeCallback(isolate, wrapper, "emit", args.size(), args.data(),
                        {0, 0});
   }
diff --git a/shell/common/api/electron_bindings.cc b/shell/common/api/electron_bindings.cc
index a2bc082ed0e0..dc8ba3709ed9 100644
--- a/shell/common/api/electron_bindings.cc
+++ b/shell/common/api/electron_bindings.cc
@@ -235,12 +235,11 @@ void ElectronBindings::DidReceiveMemoryDump(
     base::ProcessId target_pid,
     bool success,
     std::unique_ptr<memory_instrumentation::GlobalMemoryDump> global_dump) {
+  DCHECK(electron::IsBrowserProcess());
   v8::Isolate* isolate = promise.isolate();
   v8::HandleScope handle_scope(isolate);
   v8::Local<v8::Context> local_context =
       v8::Local<v8::Context>::New(isolate, context);
-  gin_helper::MicrotasksScope microtasks_scope{
-      local_context, true, v8::MicrotasksScope::kRunMicrotasks};
   v8::Context::Scope context_scope(local_context);
 
   if (!success) {
diff --git a/shell/renderer/api/electron_api_spell_check_client.cc b/shell/renderer/api/electron_api_spell_check_client.cc
index 46b8a03163a6..58ac2da5e028 100644
--- a/shell/renderer/api/electron_api_spell_check_client.cc
+++ b/shell/renderer/api/electron_api_spell_check_client.cc
@@ -215,8 +215,8 @@ void SpellCheckClient::SpellCheckWords(const SpellCheckScope& scope,
   DCHECK(!scope.spell_check_.IsEmpty());
 
   auto context = isolate_->GetCurrentContext();
-  gin_helper::MicrotasksScope microtasks_scope{
-      context, false, v8::MicrotasksScope::kDoNotRunMicrotasks};
+  v8::MicrotasksScope microtasks_scope(
+      context, v8::MicrotasksScope::kDoNotRunMicrotasks);
 
   v8::Local<v8::FunctionTemplate> templ = gin_helper::CreateFunctionTemplate(
       isolate_, base::BindRepeating(&SpellCheckClient::OnSpellCheckDone,
diff --git a/shell/renderer/electron_sandboxed_renderer_client.cc b/shell/renderer/electron_sandboxed_renderer_client.cc
index 2c985c9a59c0..2f8511a3a70d 100644
--- a/shell/renderer/electron_sandboxed_renderer_client.cc
+++ b/shell/renderer/electron_sandboxed_renderer_client.cc
@@ -146,8 +146,8 @@ void ElectronSandboxedRendererClient::WillReleaseScriptContext(
     return;
 
   auto* isolate = context->GetIsolate();
-  gin_helper::MicrotasksScope microtasks_scope{
-      context, false, v8::MicrotasksScope::kDoNotRunMicrotasks};
+  v8::MicrotasksScope microtasks_scope(
+      context, v8::MicrotasksScope::kDoNotRunMicrotasks);
   v8::HandleScope handle_scope(isolate);
   v8::Context::Scope context_scope(context);
   InvokeEmitProcessEvent(context, "exit");
@@ -164,8 +164,8 @@ void ElectronSandboxedRendererClient::EmitProcessEvent(
   v8::HandleScope handle_scope{isolate};
 
   v8::Local<v8::Context> context = GetContext(frame, isolate);
-  gin_helper::MicrotasksScope microtasks_scope{
-      context, false, v8::MicrotasksScope::kDoNotRunMicrotasks};
+  v8::MicrotasksScope microtasks_scope(
+      context, v8::MicrotasksScope::kDoNotRunMicrotasks);
   v8::Context::Scope context_scope(context);
 
   InvokeEmitProcessEvent(context, event_name);