DAS plugins: Rename PluginInfo to PluginIsolate; move to separate library

Work towards #61386

A few distinct changes:

* Rename PluginInfo to PluginIsolate
* Move PluginInfo and PluginSession to a new library,
  plugin_isolate.dart. PluginSession is _essentially_ a private class
  to PluginIsolate, so it's good to co-locate them.
* Move PluginInfo tests and PluginSession tests to a new library.
* Extract out shared parent class for PluginManager tests,
  PluginIsolate tests, and PluginSession tests.

Change-Id: Ib0c638b8797f51c57c07e277acdaea6d8202f957
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/446960
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Samuel Rawlins <[email protected]>

Author: srawlins

pkg/analysis_server/lib/src/analysis_server.dart

@@ -20,6 +20,7 @@ import 'package:analysis_server/src/lsp/handlers/handler_execute_command.dart'
 import 'package:analysis_server/src/lsp/handlers/handler_states.dart' as lsp;
 import 'package:analysis_server/src/lsp/handlers/handlers.dart' as lsp;
 import 'package:analysis_server/src/plugin/notification_manager.dart';
+import 'package:analysis_server/src/plugin/plugin_isolate.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/plugin/plugin_watcher.dart';
 import 'package:analysis_server/src/protocol_server.dart'
@@ -508,12 +509,12 @@ abstract class AnalysisServer {
   /// [driver]. Return a list containing futures that will complete when each of
   /// the plugins have sent a response, or an empty list if no [driver] is
   /// provided.
-  Map<PluginInfo, Future<Response>> broadcastRequestToPlugins(
+  Map<PluginIsolate, Future<Response>> broadcastRequestToPlugins(
     analyzer_plugin.RequestParams requestParams,
     analysis.AnalysisDriver? driver,
   ) {
     if (driver == null) {
-      return <PluginInfo, Future<Response>>{};
+      return <PluginIsolate, Future<Response>>{};
     }
     return pluginManager.broadcastRequest(
       requestParams,

pkg/analysis_server/lib/src/analytics/plugin_data.dart

@@ -5,6 +5,7 @@
 import 'dart:convert';
 
 import 'package:analysis_server/src/analytics/percentile_calculator.dart';
+import 'package:analysis_server/src/plugin/plugin_isolate.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:path/path.dart' as path;
 
@@ -28,10 +29,10 @@ class PluginData {
   /// [pluginManager].
   void recordPlugins(PluginManager pluginManager) {
     recordCount++;
-    for (var info in pluginManager.plugins) {
+    for (var isolate in pluginManager.pluginIsolates) {
       usageCounts
-          .putIfAbsent(info.safePluginId, () => PercentileCalculator())
-          .addValue(info.contextRoots.length);
+          .putIfAbsent(isolate.safePluginId, () => PercentileCalculator())
+          .addValue(isolate.contextRoots.length);
     }
   }
 
@@ -41,7 +42,7 @@ class PluginData {
   };
 }
 
-extension PluginInfoExtension on PluginInfo {
+extension PluginIsolateExtension on PluginIsolate {
   /// An ID for this plugin that doesn't contain any PII.
   ///
   /// If the plugin is installed in the pub cache and hosted on `pub.dev`, then

pkg/analysis_server/lib/src/lsp/server_capabilities_computer.dart

@@ -150,9 +150,10 @@ class ServerCapabilitiesComputer {
   ServerCapabilitiesComputer(this._server);
 
   List<TextDocumentFilterScheme> get pluginTypes =>
-      _server.pluginManager.plugins
+      _server.pluginManager.pluginIsolates
           .expand(
-            (plugin) => plugin.currentSession?.interestingFiles ?? const [],
+            (isolate) =>
+                isolate.currentSession?.interestingFiles ?? const <String>[],
           )
           // All published plugins use something like `*.extension` as
           // interestingFiles. Prefix a `**/` so that the glob matches nested