refactor: fix modernize-return-braced-init-list warnings (32-x-y) (#45608)

refactor: fix modernize-return-braced-init-list warnings (#44838)

* refactor: avoid repeating the return type from the declaration; use a braced initializer list instead [modernize-return-braced-init-list]

* refactor: avoid repeating the return type from the declaration; use a braced initializer list instead [modernize-return-braced-init-list]

NB: using the braced-initializer list uncovered an error here:
the float returned by std::floor() can't be implicitly cast to
an int. This is solved by using base::ClampFloor<int>() instead.
std::floor()

shell/browser/javascript_environment.cc

@@ -40,12 +40,13 @@ gin::IsolateHolder CreateIsolateHolder(v8::Isolate* isolate) {
   // Align behavior with V8 Isolate default for Node.js.
   // This is necessary for important aspects of Node.js
   // including heap and cpu profilers to function properly.
-
-  return gin::IsolateHolder(
-      base::SingleThreadTaskRunner::GetCurrentDefault(),
-      gin::IsolateHolder::kSingleThread,
-      gin::IsolateHolder::IsolateType::kUtility, std::move(create_params),
-      gin::IsolateHolder::IsolateCreationMode::kNormal, nullptr, isolate);
+  return gin::IsolateHolder{base::SingleThreadTaskRunner::GetCurrentDefault(),
+                            gin::IsolateHolder::kSingleThread,
+                            gin::IsolateHolder::IsolateType::kUtility,
+                            std::move(create_params),
+                            gin::IsolateHolder::IsolateCreationMode::kNormal,
+                            nullptr,
+                            isolate};
 }
 
 }  // namespace