[iOS, Passwords] Stop rewriting user-typed data on credential filling.

On other platform, when the user manually typed the username into
the login form and then selects a suggestion from the password field,
the typed username is not rewritten. This CL ensures the same behaviour
on iOS.

Bug: 1157460
Change-Id: I7fca9e69256c7efb3cdea3133a9a830b9df1af98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2584303
Commit-Queue: Maria Kazinova <kazinova@google.com>
Reviewed-by: Vadym Doroshenko  <dvadym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835725}

components/password_manager/ios/js_password_manager.h

@@ -18,8 +18,11 @@ namespace password_manager {
 struct FillData;
 
 // Serializes |fillData| so it can be used by the JS side of PasswordController.
+// Includes both username and password data if |fillUsername|, and only password
+// data otherwise.
 std::unique_ptr<base::Value> SerializeFillData(
-    const password_manager::FillData& fillData);
+    const password_manager::FillData& fillData,
+    BOOL fillUsername);
 
 // Serializes |formData| so it can be used by the JS side of PasswordController.
 std::unique_ptr<base::Value> SerializePasswordFormFillData(

components/password_manager/ios/js_password_manager.mm

@@ -75,9 +75,11 @@ std::unique_ptr<base::Value> SerializePasswordFormFillData(
 }
 
 std::unique_ptr<base::Value> SerializeFillData(
-    const password_manager::FillData& fillData) {
+    const password_manager::FillData& fillData,
+    BOOL fillUsername) {
   return SerializeFillData(
-      fillData.origin, fillData.form_id, fillData.username_element_id,
+      fillData.origin, fillData.form_id,
+      fillUsername ? fillData.username_element_id : FieldRendererId(),
       fillData.username_value, fillData.password_element_id,
       fillData.password_value);
 }

components/password_manager/ios/password_form_helper.h

@@ -94,10 +94,12 @@ class WebState;
             generatedPassword:(NSString*)generatedPassword
             completionHandler:(nullable void (^)(BOOL))completionHandler;
 
-// Autofills credentials into the page. Credentials and input fields are
-// specified by |fillData|. Invokes |completionHandler| when finished with YES
-// if successful and NO otherwise.
+// Autofills credentials into the page on credential suggestion selection.
+// Credentials and input fields are specified by |fillData|. |uniqueFieldID|
+// specifies the unput on which the suggestion was accepted. Invokes
+// |completionHandler| when finished with YES if successful and NO otherwise.
 - (void)fillPasswordFormWithFillData:(const password_manager::FillData&)fillData
+                    triggeredOnField:(autofill::FieldRendererId)uniqueFieldID
                    completionHandler:(nullable void (^)(BOOL))completionHandler;
 
 // Finds the password form with unique ID |formIdentifier| and calls

components/password_manager/ios/password_form_helper.mm

@@ -370,6 +370,7 @@ constexpr char kCommandPrefix[] = "passwordForm";
 }
 
 - (void)fillPasswordFormWithFillData:(const password_manager::FillData&)fillData
+                    triggeredOnField:(FieldRendererId)uniqueFieldID
                    completionHandler:
                        (nullable void (^)(BOOL))completionHandler {
   // Necessary copy so the values can be used inside a block.
@@ -378,9 +379,13 @@ constexpr char kCommandPrefix[] = "passwordForm";
   base::string16 usernameValue = fillData.username_value;
   base::string16 passwordValue = fillData.password_value;
 
+  // Do not fill the username if filling was triggered on a password field and
+  // the username field has user typed input.
+  BOOL fillUsername = uniqueFieldID == usernameID ||
+                      !_fieldDataManager->DidUserType(usernameID);
   __weak PasswordFormHelper* weakSelf = self;
   [self.jsPasswordManager
-       fillPasswordForm:SerializeFillData(fillData)
+       fillPasswordForm:SerializeFillData(fillData, fillUsername)
                 inFrame:GetMainFrame(_webState)
            withUsername:UTF16ToUTF8(usernameValue)
                password:UTF16ToUTF8(passwordValue)

components/password_manager/ios/password_form_helper_unittest.mm

@@ -225,12 +225,15 @@ TEST_F(PasswordFormHelperTest, FillPasswordFormWithFillData) {
   // Run password forms search to set up unique IDs.
   EXPECT_TRUE(ExecuteJavaScript(@"__gCrWeb.passwords.findPasswordForms();"));
   const std::string base_url = BaseUrl();
+  FieldRendererId username_field_id(1);
+  FieldRendererId password_field_id(2);
   FillData fill_data;
-  SetFillData(base_url, 0, 1, "john.doe@gmail.com", 2, "super!secret",
-              &fill_data);
+  SetFillData(base_url, 0, username_field_id.value(), "john.doe@gmail.com",
+              password_field_id.value(), "super!secret", &fill_data);
 
   __block int call_counter = 0;
   [helper_ fillPasswordFormWithFillData:fill_data
+                       triggeredOnField:username_field_id
                       completionHandler:^(BOOL complete) {
                         ++call_counter;
                         EXPECT_TRUE(complete);
@@ -332,11 +335,14 @@ TEST_F(PasswordFormHelperTest, RefillFormFilledOnUserTrigger) {
 
   // Fill the form on user trigger.
   const std::string base_url = BaseUrl();
+  FieldRendererId username_field_id(1);
+  FieldRendererId password_field_id(2);
   FillData fill_data;
-  SetFillData(base_url, 0, 1, "john.doe@gmail.com", 2, "super!secret",
-              &fill_data);
+  SetFillData(base_url, 0, username_field_id.value(), "john.doe@gmail.com",
+              password_field_id.value(), "super!secret", &fill_data);
   __block int call_counter = 0;
   [helper_ fillPasswordFormWithFillData:fill_data
+                       triggeredOnField:username_field_id
                       completionHandler:^(BOOL complete) {
                         ++call_counter;
                         EXPECT_TRUE(complete);
@@ -347,7 +353,8 @@ TEST_F(PasswordFormHelperTest, RefillFormFilledOnUserTrigger) {
 
   // Try to autofill the form.
   PasswordFormFillData form_data;
-  SetPasswordFormFillData(BaseUrl(), "", 0, "", 1, "someacc@store.com", "", 2,
+  SetPasswordFormFillData(BaseUrl(), "", 0, "", username_field_id.value(),
+                          "someacc@store.com", "", password_field_id.value(),
                           "store!pw", "", "", NO, &form_data);
 
   __block bool called = NO;
@@ -412,6 +419,44 @@ TEST_F(PasswordFormHelperTest, RefillFormWithUserTypedInput) {
   }));
 }
 
+// Tests that a form with username typed by user is not refilled when
+// the user selects filling suggestion on password field.
+TEST_F(PasswordFormHelperTest, FillPasswordIntoFormWithUserTypedUsername) {
+  LoadHtml(@"<form><input id='u1' type='text' name='un1'>"
+            "<input id='p1' type='password' name='pw1'></form>");
+  ExecuteJavaScript(@"__gCrWeb.fill.setUpForUniqueIDs(0);");
+  // Run password forms search to set up unique IDs.
+  EXPECT_TRUE(ExecuteJavaScript(@"__gCrWeb.passwords.findPasswordForms();"));
+
+  FieldRendererId username_field_id(1);
+  FieldRendererId password_field_id(2);
+
+  ExecuteJavaScript(
+      @"document.getElementById('u1').value = 'typed@typed.com';");
+  [helper_ updateFieldDataOnUserInput:username_field_id
+                           inputValue:@"typed@typed.com"];
+
+  // Try to autofill the form.
+  FillData fill_data;
+  SetFillData(BaseUrl(), 0, username_field_id.value(), "someacc@store.com",
+              password_field_id.value(), "store!pw", &fill_data);
+
+  __block bool called = NO;
+  __block bool success = NO;
+  [helper_ fillPasswordFormWithFillData:fill_data
+                       triggeredOnField:password_field_id
+                      completionHandler:^(BOOL res) {
+                        called = YES;
+                        success = res;
+                      }];
+  EXPECT_TRUE(WaitUntilConditionOrTimeout(kWaitForJSCompletionTimeout, ^{
+    return called;
+  }));
+  EXPECT_EQ(success, YES);
+  id result = ExecuteJavaScript(kInputFieldValueVerificationScript);
+  EXPECT_NSEQ(@"u1=typed@typed.com;p1=store!pw;", result);
+}
+
 }  // namespace
 
 NS_ASSUME_NONNULL_END

components/password_manager/ios/shared_password_controller.mm

@@ -410,6 +410,7 @@ NSString* const kSuggestionSuffix = @" ••••••••";
       }
 
       [self.formHelper fillPasswordFormWithFillData:*fillData
+                                   triggeredOnField:uniqueFieldID
                                   completionHandler:^(BOOL success) {
                                     completion();
                                   }];