Refactoring. Lower number github api call. (#4879)

Refactoring while working on flutter/flutter#178426

Author: ievdokdm

app_dart/lib/src/request_handlers/github/webhook_subscription.dart

@@ -571,12 +571,19 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
 
   Future<void> _checkForTests(PullRequestEvent pullRequestEvent) async {
     final pr = pullRequestEvent.pullRequest!;
+    // We do not need to add test labels if this is an auto roller author.
+    if (config.rollerAccounts.contains(pr.user!.login)) {
+      return;
+    }
     final eventAction = pullRequestEvent.action;
     final slug = pr.base!.repo!.slug();
     final isTipOfTree = pr.base!.ref == Config.defaultBranch(slug);
     final gitHubClient = await config.createGitHubClient(pullRequest: pr);
     await _validateRefs(gitHubClient, pr);
     if (kNeedsTests.contains(slug) && isTipOfTree) {
+      log.info(
+        'Applying framework repo labels for: owner=${slug.owner} repo=${slug.name} and pr=${pr.number}',
+      );
       switch (slug.name) {
         case 'flutter':
           final isFusion = slug == Config.flutterSlug;
@@ -587,15 +594,16 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
             gitHubClient,
             eventAction,
             pr,
-            isFusion: isFusion,
-            files: files,
+            files,
+            slug,
           );
           if (isFusion) {
             await _applyEngineRepoLabels(
               gitHubClient,
               eventAction,
               pr,
-              files: files,
+              files,
+              slug,
             );
           }
         case 'packages':
@@ -607,23 +615,14 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
   Future<void> _applyFrameworkRepoLabels(
     GitHub gitHubClient,
     String? eventAction,
-    PullRequest pr, {
-    bool isFusion = false,
-    List<PullRequestFile>? files,
-  }) async {
+    PullRequest pr,
+    List<PullRequestFile> files,
+    RepositorySlug slug,
+  ) async {
     if (pr.user!.login == 'engine-flutter-autoroll') {
       return;
     }
 
-    final slug = pr.base!.repo!.slug();
-    log.info(
-      'Applying framework repo labels for: owner=${slug.owner} repo=${slug.name} isFusion=$isFusion and pr=${pr.number}',
-    );
-
-    files ??= await gitHubClient.pullRequests
-        .listFiles(slug, pr.number!)
-        .toList();
-
     final labels = <String>{};
     var hasTests = false;
     var needsTests = false;
@@ -668,11 +667,6 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
       );
     }
 
-    // We do not need to add test labels if this is an auto roller author.
-    if (config.rollerAccounts.contains(pr.user!.login)) {
-      return;
-    }
-
     if (!hasTests &&
         needsTests &&
         !pr.draft! &&
@@ -754,15 +748,15 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
   Future<void> _applyEngineRepoLabels(
     GitHub gitHubClient,
     String? eventAction,
-    PullRequest pr, {
-    List<PullRequestFile>? files,
-  }) async {
+    PullRequest pr,
+    List<PullRequestFile> files,
+    RepositorySlug slug,
+  ) async {
     // Do not apply the test labels for the autoroller accounts.
     if (pr.user!.login == 'skia-flutter-autoroll') {
       return;
     }
 
-    final slug = pr.base!.repo!.slug();
     var hasTests = false;
     var needsTests = false;
 
@@ -772,9 +766,6 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
 
     var engineFiles = 0;
 
-    files ??= await gitHubClient.pullRequests
-        .listFiles(slug, pr.number!)
-        .toList();
     for (var file in files) {
       final path = file.filename!;
       if (isFusion && _isFusionEnginePath(path)) {
@@ -800,11 +791,6 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
       return;
     }
 
-    // We do not need to add test labels if this is an auto roller author.
-    if (config.rollerAccounts.contains(pr.user!.login)) {
-      return;
-    }
-
     if (!hasTests &&
         needsTests &&
         !pr.draft! &&
@@ -882,11 +868,6 @@ final class GithubWebhookSubscription extends SubscriptionHandler {
       }
     }
 
-    // We do not need to add test labels if this is an auto roller author.
-    if (config.rollerAccounts.contains(pr.user!.login)) {
-      return;
-    }
-
     if (!hasTests &&
         needsTests &&
         !pr.draft! &&