[integration_test] Minor cleanup (flutter#2956)

- Doc typos
- Unused Java variables

Author: jiahaog

packages/integration_test/android/src/main/java/dev/flutter/plugins/integration_test/IntegrationTestPlugin.java

@@ -37,8 +37,8 @@ public void onAttachedToEngine(FlutterPluginBinding binding) {
     onAttachedToEngine(binding.getApplicationContext(), binding.getBinaryMessenger());
   }
 
-  private void onAttachedToEngine(Context applicationContext, BinaryMessenger messenger) {
-    methodChannel = new MethodChannel(messenger, "plugins.flutter.io/integration_test");
+  private void onAttachedToEngine(Context unusedApplicationContext, BinaryMessenger messenger) {
+    methodChannel = new MethodChannel(messenger, CHANNEL);
     methodChannel.setMethodCallHandler(this);
   }
 

packages/integration_test/lib/common.dart

@@ -53,7 +53,7 @@ class Response {
     }
   }
 
-  /// Method for formating the test failures' details.
+  /// Method for formatting the test failures' details.
   String formatFailures(List<Failure> failureDetails) {
     if (failureDetails.isEmpty) {
       return '';

packages/integration_test/lib/integration_test_driver.dart

@@ -19,7 +19,8 @@ import 'package:path/path.dart' as path;
 String testOutputsDirectory =
     Platform.environment['FLUTTER_TEST_OUTPUTS_DIR'] ?? 'build';
 
-/// The callback type to handle [integration_test.Response.data] after the test succcess.
+/// The callback type to handle [integration_test.Response.data] after the test
+/// succeeds.
 typedef ResponseDataCallback = FutureOr<void> Function(Map<String, dynamic>);
 
 /// Writes a json-serializable json data to to