views::Textfield: Implement transpose editing command.

ui/views/cocoa/bridged_native_widget_unittest.mm

Index: ui/views/cocoa/bridged_native_widget_unittest.mm
diff --git a/ui/views/cocoa/bridged_native_widget_unittest.mm b/ui/views/cocoa/bridged_native_widget_unittest.mm
index 416cfbcc478c4ef155128b73b34f145d40e4d4a0..4554eee36a5155c614f9e5d7cec497da7f4d048a 100644
--- a/ui/views/cocoa/bridged_native_widget_unittest.mm
+++ b/ui/views/cocoa/bridged_native_widget_unittest.mm
@@ -112,7 +112,8 @@ NSArray* const kDeleteActions = @[
   @"deleteToBeginningOfParagraph:", @"deleteToEndOfParagraph:"
 ];
 
-NSArray* const kMiscActions = @[ @"insertText:", @"cancelOperation:" ];
+NSArray* const kMiscActions =
+    @[ @"insertText:", @"cancelOperation:", @"transpose:" ];
 
 // Empty range shortcut for readibility.
 NSRange EmptyRange() {
@@ -1033,6 +1034,11 @@ TEST_F(BridgedNativeWidgetTest, NilTextInputClient) {
     [ns_view_ doCommandBySelector:NSSelectorFromString(selector)];
 }
 
+// Test transpose command against expectations set by |dummy_text_view_|.
+TEST_F(BridgedNativeWidgetTest, TextInput_Transpose) {
+  TestEditingCommands(@[ @"transpose:" ]);
+}
+
 // Test firstRectForCharacterRange:actualRange for cases where query range is
 // empty or outside composition range.
 TEST_F(BridgedNativeWidgetTest, TextInput_FirstRectForCharacterRange_Caret) {