Parameterize CoverageCollector with a library name predicate (#36774)

An optimization to the coverage collection speed was added in #30811. This commit further expands on it to parameterize the CoverageCollector with a custom predicate, allowing internal use cases to filter the RPC calls to the Dart VM based on scripts of interest to coverage collection.

packages/flutter_tools/bin/fuchsia_tester.dart

@@ -117,9 +117,14 @@ Future<void> run(List<String> args) async {
     CoverageCollector collector;
     if (argResults['coverage']) {
       collector = CoverageCollector(
-        flutterProject: FlutterProject.current(),
-        coverageDirectory: coverageDirectory,
-      );
+        libraryPredicate: (String libraryName) {
+          // If we have a specified coverage directory then accept all libraries.
+          if (coverageDirectory != null) {
+            return true;
+          }
+          final String projectName = FlutterProject.current().manifest.appName;
+          return libraryName.contains(projectName);
+        });
       if (!argResults.options.contains(_kOptionTestDirectory)) {
         throwToolExit('Use of --coverage requires setting --test-directory');
       }

packages/flutter_tools/lib/src/commands/test.dart

@@ -185,8 +185,9 @@ class TestCommand extends FastFlutterCommand {
 
     CoverageCollector collector;
     if (argResults['coverage'] || argResults['merge-coverage']) {
+      final String projectName = FlutterProject.current().manifest.appName;
       collector = CoverageCollector(
-        flutterProject: FlutterProject.current(),
+        libraryPredicate: (String libraryName) => libraryName.contains(projectName),
       );
     }
 

packages/flutter_tools/lib/src/test/coverage_collector.dart

@@ -14,18 +14,16 @@ import '../base/platform.dart';
 import '../base/process_manager.dart';
 import '../dart/package_map.dart';
 import '../globals.dart';
-import '../project.dart';
 import '../vmservice.dart';
 
 import 'watcher.dart';
 
 /// A class that's used to collect coverage data during tests.
 class CoverageCollector extends TestWatcher {
-  CoverageCollector({this.flutterProject, this.coverageDirectory});
+  CoverageCollector({this.libraryPredicate});
 
   Map<String, dynamic> _globalHitmap;
-  final Directory coverageDirectory;
-  final FlutterProject flutterProject;
+  bool Function(String) libraryPredicate;
 
   @override
   Future<void> handleFinishedTest(ProcessEvent event) async {
@@ -50,13 +48,7 @@ class CoverageCollector extends TestWatcher {
   Future<void> collectCoverageIsolate(Uri observatoryUri) async {
     assert(observatoryUri != null);
     print('collecting coverage data from $observatoryUri...');
-    final Map<String, dynamic> data = await collect(observatoryUri, (String libraryName) {
-      // If we have a specified coverage directory or could not find the package name, then
-      // accept all libraries.
-      return (coverageDirectory != null)
-          || (flutterProject == null)
-          || libraryName.contains(flutterProject.manifest.appName);
-    });
+    final Map<String, dynamic> data = await collect(observatoryUri, libraryPredicate);
     if (data == null) {
       throw Exception('Failed to collect coverage.');
     }
@@ -84,17 +76,7 @@ class CoverageCollector extends TestWatcher {
       .then<void>((int code) {
         throw Exception('Failed to collect coverage, process terminated prematurely with exit code $code.');
       });
-    final Future<void> collectionComplete = collect(observatoryUri, (String libraryName) {
-      // If we have a specified coverage directory or could not find the package name, then
-      // accept all libraries.
-      if (coverageDirectory != null) {
-        return true;
-      }
-      if (flutterProject == null) {
-        return true;
-      }
-      return libraryName.contains(flutterProject.manifest.appName);
-    })
+    final Future<void> collectionComplete = collect(observatoryUri, libraryPredicate)
       .then<void>((Map<String, dynamic> result) {
         if (result == null)
           throw Exception('Failed to collect coverage.');

packages/flutter_tools/tool/tool_coverage.dart

@@ -47,7 +47,7 @@ Future<void> main(List<String> arguments) async {
 /// A platform that loads tests in isolates spawned within this Dart process.
 class VMPlatform extends PlatformPlugin {
   final CoverageCollector coverageCollector = CoverageCollector(
-    flutterProject: FlutterProject.current(),
+    libraryPredicate: (String libraryName) => libraryName.contains(FlutterProject.current().manifest.appName),
   );
   final Map<String, Future<void>> _pending = <String, Future<void>>{};
   final String precompiledPath = path.join('.dart_tool', 'build', 'generated', 'flutter_tools');