Add "previewing on hover" support for single-field autocomplete input

components/autofill/core/browser/autofill_external_delegate_unittest.cc

Index: components/autofill/core/browser/autofill_external_delegate_unittest.cc
diff --git a/components/autofill/core/browser/autofill_external_delegate_unittest.cc b/components/autofill/core/browser/autofill_external_delegate_unittest.cc
index ad86d836bebc462876e46505413897ae12815aec..ec107fb4be109f25f56e4fea13701bcc0344c83b 100644
--- a/components/autofill/core/browser/autofill_external_delegate_unittest.cc
+++ b/components/autofill/core/browser/autofill_external_delegate_unittest.cc
@@ -375,6 +375,26 @@ TEST_F(AutofillExternalDelegateUnitTest, ExternalDelegateClearPreviewedForm) {
   EXPECT_CALL(*autofill_driver_, SetRendererActionOnFormDataReception(
       AutofillDriver::FORM_DATA_ACTION_PREVIEW));
   external_delegate_->DidSelectSuggestion(1);
+
+  // Ensure selecting an AutoComplete entries will cause any previews to
+  // get cleared.
+  base::string16 suggestion_string(ASCIIToUTF16("baz foo"));
+  EXPECT_CALL(*autofill_driver_, RendererShouldClearPreviewedForm()).Times(1);
+  external_delegate_->DidSelectAutocompleteSuggestion(suggestion_string);
+}
+
+// Test that the ClearAutoCompletePreview call is only sent if the autocomplete
+// field was being previewed.
+TEST_F(AutofillExternalDelegateUnitTest,
+       ExternalDelegateClearAutocompletePreviewedField) {
+  base::string16 suggestion_string(ASCIIToUTF16("baz foo"));
+  EXPECT_CALL(*autofill_driver_,
+              RendererShouldSetNodeText(suggestion_string));
+
+  EXPECT_CALL(*autofill_driver_, RendererShouldClearPreviewedForm()).Times(1);
+  EXPECT_CALL(*autofill_driver_,
+              RendererShouldSetNodeText(ASCIIToUTF16("")));
+  external_delegate_->DidSelectAutocompleteSuggestion(suggestion_string);
 }
 
 // Test that the popup is hidden once we are done editing the autofill field.