[flutter_tools] add more docs to cocoapods, move to globals (#67237)

Add some placeholder docs to the Cocoapods validator and Cocoapods class. Add the injected validator to globals. #47161

packages/flutter_tools/lib/src/doctor.dart

@@ -26,7 +26,6 @@ import 'intellij/intellij.dart';
 import 'ios/plist_parser.dart';
 import 'linux/linux_doctor.dart';
 import 'linux/linux_workflow.dart';
-import 'macos/cocoapods_validator.dart';
 import 'macos/macos_workflow.dart';
 import 'macos/xcode_validator.dart';
 import 'proxy_validator.dart';
@@ -86,7 +85,7 @@ class _DefaultDoctorValidatorsProvider implements DoctorValidatorsProvider {
       if (androidWorkflow.appliesToHostPlatform)
         GroupedValidator(<DoctorValidator>[androidValidator, androidLicenseValidator]),
       if (globals.iosWorkflow.appliesToHostPlatform || macOSWorkflow.appliesToHostPlatform)
-        GroupedValidator(<DoctorValidator>[XcodeValidator(xcode: globals.xcode, userMessages: userMessages), cocoapodsValidator]),
+        GroupedValidator(<DoctorValidator>[XcodeValidator(xcode: globals.xcode, userMessages: userMessages), globals.cocoapodsValidator]),
       if (webWorkflow.appliesToHostPlatform)
         ChromeValidator(
           chromiumLauncher: ChromiumLauncher(

packages/flutter_tools/lib/src/globals.dart

@@ -32,6 +32,7 @@ import 'ios/plist_parser.dart';
 import 'ios/simulators.dart';
 import 'ios/xcodeproj.dart';
 import 'macos/cocoapods.dart';
+import 'macos/cocoapods_validator.dart';
 import 'macos/xcode.dart';
 import 'persistent_tool_state.dart';
 import 'project.dart';
@@ -60,6 +61,8 @@ FlutterProjectFactory get projectFactory {
   );
 }
 
+CocoaPodsValidator get cocoapodsValidator => context.get<CocoaPodsValidator>();
+
 LocalEngineLocator get localEngineLocator => context.get<LocalEngineLocator>();
 
 /// Currently active implementation of the file system.

packages/flutter_tools/lib/src/macos/cocoapods.dart

@@ -67,6 +67,15 @@ enum CocoaPodsStatus {
   brokenInstall,
 }
 
+/// Cocoapods is a depenency management solution for iOS and macOS applications.
+///
+/// Cocoapods is generally installed via ruby gems and interacted with via
+/// the `pod` CLI command.
+///
+/// See also:
+///   * https://cocoapods.org/ - the cocoapods website.
+///   * https://flutter.dev/docs/get-started/install/macos#deploy-to-ios-devices - instructions for
+///     installing iOS/macOS dependencies.
 class CocoaPods {
   CocoaPods({
     @required FileSystem fileSystem,

packages/flutter_tools/lib/src/macos/cocoapods_validator.dart

@@ -2,13 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import '../base/context.dart';
 import '../base/user_messages.dart';
 import '../doctor.dart';
 import 'cocoapods.dart';
 
-CocoaPodsValidator get cocoapodsValidator => context.get<CocoaPodsValidator>();
-
+/// A validator that confirms cocoapods is in a valid state.
+///
+/// See also:
+///   * [CocoaPods], for the interface to the cocoapods command line tool.
 class CocoaPodsValidator extends DoctorValidator {
   CocoaPodsValidator(
     CocoaPods cocoaPods,