[Autofill Assistant] Add ComputeProto for StringEmpty

This adds a new option for computing a value by checking
whether or not a string value is empty.

Bug: None
Change-Id: I2f1a18cde4dd9add1e300621d70c27ebe61369b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2537353
Commit-Queue: Sandro Maggi <sandromaggi@google.com>
Reviewed-by: Clemens Arbesser <arbesser@google.com>
Cr-Commit-Position: refs/heads/master@{#828223}

components/autofill_assistant/browser/basic_interactions.cc

@@ -385,6 +385,27 @@ bool CreateLoginOptionResponse(UserModel* user_model,
   return true;
 }
 
+bool StringEmpty(UserModel* user_model,
+                 const std::string& result_model_identifier,
+                 const StringEmptyProto& proto) {
+  auto value = user_model->GetValue(proto.value());
+  if (!value.has_value()) {
+    DVLOG(2) << "Failed to find value in user model";
+    return false;
+  }
+
+  if (value->strings().values().size() != 1) {
+    DVLOG(2) << "Error evaluating " << __func__
+             << ": expected single string, but got " << *value;
+    return false;
+  }
+
+  user_model->SetValue(result_model_identifier,
+                       SimpleValue(value->strings().values(0).empty(),
+                                   ContainsClientOnlyValue({*value})));
+  return true;
+}
+
 }  // namespace
 
 base::WeakPtr<BasicInteractions> BasicInteractions::GetWeakPtr() {
@@ -479,6 +500,14 @@ bool BasicInteractions::ComputeValue(const ComputeValueProto& proto) {
                                        proto.result_model_identifier(),
                                        proto.create_login_option_response());
       break;
+    case ComputeValueProto::kStringEmpty:
+      if (!proto.string_empty().has_value()) {
+        DVLOG(2)
+            << "Error computing ComputeValue::StringEmpty: no value specified";
+        return false;
+      }
+      return StringEmpty(delegate_->GetUserModel(),
+                         proto.result_model_identifier(), proto.string_empty());
     case ComputeValueProto::KIND_NOT_SET:
       DVLOG(2) << "Error computing value: kind not set";
       return false;

components/autofill_assistant/browser/basic_interactions_unittest.cc

@@ -633,6 +633,32 @@ TEST_F(BasicInteractionsTest, ComputeValueCreateLoginOptionResponse) {
   EXPECT_EQ(user_model_.GetValue("result"), expected_response_value);
 }
 
+TEST_F(BasicInteractionsTest, ComputeStringEmpty) {
+  ComputeValueProto proto;
+  proto.set_result_model_identifier("result");
+  proto.mutable_string_empty()->mutable_value()->set_model_identifier("value");
+
+  // Missing value.
+  EXPECT_FALSE(basic_interactions_.ComputeValue(proto));
+
+  // Multiple strings.
+  ValueProto multiple_strings;
+  multiple_strings.mutable_strings()->add_values("Hello");
+  multiple_strings.mutable_strings()->add_values("World");
+  user_model_.SetValue("value", multiple_strings);
+  EXPECT_FALSE(basic_interactions_.ComputeValue(proto));
+
+  // Single empty string.
+  user_model_.SetValue("value", SimpleValue(std::string()));
+  EXPECT_TRUE(basic_interactions_.ComputeValue(proto));
+  EXPECT_EQ(user_model_.GetValue("result"), SimpleValue(true));
+
+  // Single non-empty string.
+  user_model_.SetValue("value", SimpleValue(std::string("Hello")));
+  EXPECT_TRUE(basic_interactions_.ComputeValue(proto));
+  EXPECT_EQ(user_model_.GetValue("result"), SimpleValue(false));
+}
+
 TEST_F(BasicInteractionsTest, ToggleUserAction) {
   ToggleUserActionProto proto;
   ValueProto user_actions_value;

components/autofill_assistant/browser/generic_ui.proto

@@ -136,6 +136,8 @@ message ComputeValueProto {
     CreateCreditCardResponseProto create_credit_card_response = 8;
     // Writes safe-to-transmit parts of the input login option to the result.
     CreateLoginOptionResponseProto create_login_option_response = 9;
+    // Check if a string value is empty.
+    StringEmptyProto string_empty = 10;
   }
 
   // The model identifier to write the result to.
@@ -254,6 +256,12 @@ message CreateLoginOptionResponseProto {
   optional ValueReferenceProto value = 1;
 }
 
+// Checks whether or not a string value is empty.
+message StringEmptyProto {
+  // The input string.
+  optional ValueReferenceProto value = 1;
+}
+
 // Displays a standard info popup.
 message ShowInfoPopupProto {
   optional InfoPopupProto info_popup = 1;

components/autofill_assistant/browser/generic_ui_replace_placeholders.cc

@@ -323,6 +323,14 @@ void ReplacePlaceholdersInCallback(
                 placeholders);
           }
           return;
+        case ComputeValueProto::kStringEmpty:
+          if (in_out_proto->compute_value().string_empty().has_value()) {
+            ReplacePlaceholdersInValue(in_out_proto->mutable_compute_value()
+                                           ->mutable_string_empty()
+                                           ->mutable_value(),
+                                       placeholders);
+          }
+          return;
         case ComputeValueProto::KIND_NOT_SET:
           return;
       }