[common] Store Settings global on the global context

Since we pass the `DevToolsContext` of a universe to the
TargetManager, SDKModel instances will be able to pull
Settings from there instead of using the global.

Bug: 490892816
Change-Id: I54eb8d698c440ed6913bed2fd7ff0236a13d3ed3
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7649035
Reviewed-by: Kim-Anh Tran <kimanh@chromium.org>
Commit-Queue: Simon Zünd <szuend@chromium.org>

Author: szuend

front_end/core/common/Settings.ts

@@ -22,8 +22,6 @@ import {
   SettingType,
 } from './SettingRegistration.js';
 
-let settingsInstance: Settings|undefined;
-
 export interface SettingsCreationOptions {
   syncedStorage: SettingsStorage;
   globalStorage: SettingsStorage;
@@ -85,7 +83,7 @@ export class Settings {
   }
 
   static hasInstance(): boolean {
-    return typeof settingsInstance !== 'undefined';
+    return Root.DevToolsContext.globalInstance().has(Settings);
   }
 
   static instance(opts: {
@@ -107,20 +105,26 @@ export class Settings {
       logSettingAccess,
       runSettingsMigration
     } = opts;
-    if (!settingsInstance || forceNew) {
+    if (!Root.DevToolsContext.globalInstance().has(Settings) || forceNew) {
       if (!syncedStorage || !globalStorage || !localStorage || !settingRegistrations) {
         throw new Error(`Unable to create settings: global and local storage must be provided: ${new Error().stack}`);
       }
 
-      settingsInstance = new Settings(
-          {syncedStorage, globalStorage, localStorage, settingRegistrations, logSettingAccess, runSettingsMigration});
+      Root.DevToolsContext.globalInstance().set(Settings, new Settings({
+                                                  syncedStorage,
+                                                  globalStorage,
+                                                  localStorage,
+                                                  settingRegistrations,
+                                                  logSettingAccess,
+                                                  runSettingsMigration
+                                                }));
     }
 
-    return settingsInstance;
+    return Root.DevToolsContext.globalInstance().get(Settings);
   }
 
   static removeInstance(): void {
-    settingsInstance = undefined;
+    Root.DevToolsContext.globalInstance().delete(Settings);
   }
 
   private registerModuleSetting(setting: Setting<unknown>): void {

front_end/foundation/Universe.ts

@@ -17,12 +17,14 @@ export class Universe {
   readonly context = new Root.DevToolsContext.DevToolsContext();
 
   constructor(options: CreationOptions) {
-    // TODO(crbug.com/458180550): Store instance on a "DevToolsContext" instead.
-    //                            For now the global is fine as we don't anticipate the MCP server to change settings.
+    // TODO(crbug.com/458180550): Store instance only on this.context instead.
+    //                            For now the global is required as not everything in foundation cleanly
+    //                            reads from the scoped `Settings` instance.
     const settings = Common.Settings.Settings.instance({
       forceNew: true,
       ...options.settingsCreationOptions,
     });
+    this.context.set(Common.Settings.Settings, settings);
 
     const targetManager = new SDK.TargetManager.TargetManager(this.context, options.overrideAutoStartModels);
     this.context.set(SDK.TargetManager.TargetManager, targetManager);