Migrate docs_test to shard. (#139282)

This is part of the deprecation of adhoc tests.

Bug: https://github.com/flutter/flutter/issues/139153

.ci.yaml

@@ -407,7 +407,7 @@ targets:
       - os=Linux
 
   - name: Linux docs_test
-    recipe: flutter/flutter
+    recipe: flutter/flutter_drone
     timeout: 90 # https://github.com/flutter/flutter/issues/120901
     properties:
       cores: "32"
@@ -418,9 +418,8 @@ targets:
       firebase_project: ""
       release_ref: ""
       tags: >
-        ["framework", "hostonly", "linux"]
-      validation: docs
-      validation_name: Docs
+        ["framework", "hostonly", "shard", "linux"]
+      shard: docs
     runIf:
       - bin/**
       - dev/**

TESTOWNERS

@@ -295,8 +295,8 @@
 /dev/devicelab/bin/tasks/windows_startup_test.dart @loic-sharma @flutter/desktop
 
 ## Host only framework tests
-# Linux docs
-# Linux docs_test
+# Linux docs_deploy_beta
+# Linux docs_deploy_stable
 # Linux docs_publish
 /dev/bots/docs.sh @HansMuller @flutter/framework
 # Linux packages_autoroller
@@ -324,6 +324,7 @@
 # ci_yaml flutter roller @caseyhillers @flutter/infra
 # coverage @godofredoc @flutter/infra
 # customer_testing @HansMuller @flutter/framework
+# docs @HansMuller @flutter/framework
 # flutter_packaging @godofredoc @flutter/infra
 # flutter_plugins @stuartmorgan @flutter/plugin
 # framework_tests @HansMuller @flutter/framework

dev/bots/test.dart

@@ -266,6 +266,7 @@ Future<void> main(List<String> args) async {
       'customer_testing': _runCustomerTesting,
       'analyze': _runAnalyze,
       'fuchsia_precache': _runFuchsiaPrecache,
+      'docs': _runDocs,
       kTestHarnessShardName: _runTestHarnessTests, // Used for testing this script; also run as part of SHARD=framework_tests, SUBSHARD=misc.
     });
   } catch (error, stackTrace) {
@@ -1628,6 +1629,22 @@ Future<void> _runFuchsiaPrecache() async {
   );
 }
 
+// Runs docs.
+Future<void> _runDocs() async {
+  printProgress('${green}Running flutter doc tests$reset');
+  await runCommand(
+    './dev/bots/docs.sh',
+    <String>[
+      '--output',
+      'dev/docs/api_docs.zip',
+      '--keep-staging',
+      '--staging-dir',
+      'dev/docs',
+    ],
+    workingDirectory: flutterRoot,
+  );
+}
+
 /// Runs the skp_generator from the flutter/tests repo.
 ///
 /// See also the customer_tests shard.