support disabling text entry emulation (#13410)

dev/integration_tests/ui/test_driver/keyboard_resize_test.dart

@@ -21,6 +21,7 @@ void main() {
     });
 
     test('Ensure keyboard dismissal resizes the view to original size', () async {
+      await driver.setTextEntryEmulation(enabled: false);
       final SerializableFinder heightText = find.byValueKey(keys.kHeightText);
       await driver.waitFor(heightText);
 

packages/flutter_driver/lib/src/common/text.dart

@@ -71,3 +71,39 @@ class EnterTextResult extends Result {
   @override
   Map<String, dynamic> toJson() => const <String, String>{};
 }
+
+/// A Flutter Driver command that enables and disables text entry emulation.
+class SetTextEntryEmulation extends Command {
+  /// Creates a command that enables and disables text entry emulation.
+  SetTextEntryEmulation(this.enabled, { Duration timeout }) : super(timeout: timeout);
+
+  /// Whether text entry emulation should be enabled.
+  final bool enabled;
+
+  /// Deserializes this command from the value generated by [serialize].
+  SetTextEntryEmulation.deserialize(Map<String, dynamic> json)
+      : enabled = json['enabled'] == 'true',
+        super.deserialize(json);
+
+  @override
+  final String kind = 'set_text_entry_emulation';
+
+  @override
+  Map<String, String> serialize() => super.serialize()..addAll(<String, String>{
+    'enabled': '$enabled',
+  });
+}
+
+/// The result of the [SetTextEntryEmulation] command.
+class SetTextEntryEmulationResult extends Result {
+  /// Creates a successful result.
+  SetTextEntryEmulationResult();
+
+  /// Deserializes the result from JSON.
+  static SetTextEntryEmulationResult fromJson(Map<String, dynamic> json) {
+    return new SetTextEntryEmulationResult();
+  }
+
+  @override
+  Map<String, dynamic> toJson() => const <String, String>{};
+}

packages/flutter_driver/lib/src/driver/driver.dart

@@ -451,6 +451,15 @@ class FlutterDriver {
     await _sendCommand(new EnterText(text, timeout: timeout));
   }
 
+  /// If `enabled` is true, enables text entry emulation via [enterText]. If
+  /// `enabled` is false, disables it.
+  ///
+  /// By default text entry emulation is enabled.
+  Future<Null> setTextEntryEmulation({ @required bool enabled, Duration timeout }) async {
+    assert(enabled != null);
+    await _sendCommand(new SetTextEntryEmulation(enabled, timeout: timeout));
+  }
+
   /// Sends a string and returns a string.
   ///
   /// This enables generic communication between the driver and the application.

packages/flutter_driver/lib/src/extension/extension.dart

@@ -100,6 +100,7 @@ class FlutterDriverExtension {
       'scrollIntoView': _scrollIntoView,
       'set_frame_sync': _setFrameSync,
       'set_semantics': _setSemantics,
+      'set_text_entry_emulation': _setTextEntryEmulation,
       'tap': _tap,
       'waitFor': _waitFor,
       'waitForAbsent': _waitForAbsent,
@@ -116,6 +117,7 @@ class FlutterDriverExtension {
       'scrollIntoView': (Map<String, String> params) => new ScrollIntoView.deserialize(params),
       'set_frame_sync': (Map<String, String> params) => new SetFrameSync.deserialize(params),
       'set_semantics': (Map<String, String> params) => new SetSemantics.deserialize(params),
+      'set_text_entry_emulation': (Map<String, String> params) => new SetTextEntryEmulation.deserialize(params),
       'tap': (Map<String, String> params) => new Tap.deserialize(params),
       'waitFor': (Map<String, String> params) => new WaitFor.deserialize(params),
       'waitForAbsent': (Map<String, String> params) => new WaitForAbsent.deserialize(params),
@@ -332,6 +334,16 @@ class FlutterDriverExtension {
     return new GetTextResult(text.data);
   }
 
+  Future<SetTextEntryEmulationResult> _setTextEntryEmulation(Command command) async {
+    final SetTextEntryEmulation setTextEntryEmulationCommand = command;
+    if (setTextEntryEmulationCommand.enabled) {
+      _testTextInput.register();
+    } else {
+      _testTextInput.unregister();
+    }
+    return new SetTextEntryEmulationResult();
+  }
+
   Future<EnterTextResult> _enterText(Command command) async {
     final EnterText enterTextCommand = command;
     _testTextInput.enterText(enterTextCommand.text);

packages/flutter_test/lib/src/test_text_input.dart

@@ -24,6 +24,15 @@ class TestTextInput {
     SystemChannels.textInput.setMockMethodCallHandler(_handleTextInputCall);
   }
 
+  /// Removes this object as a mock handler for [SystemChannels.textInput].
+  ///
+  /// After calling this method, the channel will exchange messages with the
+  /// Flutter engine. Use this with [FlutterDriver] tests that need to display
+  /// on-screen keyboard provided by the operating system.
+  void unregister() {
+    SystemChannels.textInput.setMockMethodCallHandler(null);
+  }
+
   int _client = 0;
 
   /// Arguments supplied to the TextInput.setClient method call.