Reland "Do not haul suggestions back to browser in AutofillHostMsg_ShowPasswordSuggestions"

components/password_manager/core/browser/password_autofill_manager.cc

Index: components/password_manager/core/browser/password_autofill_manager.cc
diff --git a/components/password_manager/core/browser/password_autofill_manager.cc b/components/password_manager/core/browser/password_autofill_manager.cc
index 01bf791bed010de8ddfda9ae442a1c79cb34dcd1..2d680b60a622d7d7f1fa8f4f1ed716c236792e61 100644
--- a/components/password_manager/core/browser/password_autofill_manager.cc
+++ b/components/password_manager/core/browser/password_autofill_manager.cc
@@ -2,16 +2,59 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "components/password_manager/core/browser/password_autofill_manager.h"
+
+#include <vector>
+
 #include "base/logging.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
 #include "components/autofill/core/browser/autofill_driver.h"
 #include "components/autofill/core/browser/popup_item_ids.h"
 #include "components/autofill/core/common/autofill_data_validation.h"
-#include "components/password_manager/core/browser/password_autofill_manager.h"
 #include "components/password_manager/core/browser/password_manager_client.h"
 #include "components/password_manager/core/browser/password_manager_driver.h"
 
 namespace password_manager {
 
+namespace {
+
+// This function attempts to fill |suggestions| and |realms| form |fill_data|
+// based on |current_username|. Unless |show_all| is true, it only picks
+// suggestions where the username has |current_username| as a prefix.
+void GetSuggestions(const autofill::PasswordFormFillData& fill_data,
+                    const base::string16& current_username,
+                    std::vector<base::string16>* suggestions,
+                    std::vector<base::string16>* realms,
+                    bool show_all) {
+  if (show_all ||
+      StartsWith(
+          fill_data.basic_data.fields[0].value, current_username, false)) {
+    suggestions->push_back(fill_data.basic_data.fields[0].value);
+    realms->push_back(base::UTF8ToUTF16(fill_data.preferred_realm));
+  }
+
+  for (const auto& login : fill_data.additional_logins) {
+    if (show_all || StartsWith(login.first, current_username, false)) {
+      suggestions->push_back(login.first);
+      realms->push_back(base::UTF8ToUTF16(login.second.realm));
+    }
+  }
+
+  for (const auto& usernames : fill_data.other_possible_usernames) {
+    for (size_t i = 0; i < usernames.second.size(); ++i) {
+      if (show_all ||
+          StartsWith(usernames.second[i], current_username, false)) {
+        suggestions->push_back(usernames.second[i]);
+        realms->push_back(base::UTF8ToUTF16(usernames.first.realm));
+      }
+    }
+  }
+}
+
+}  // namespace
+
 ////////////////////////////////////////////////////////////////////////////////
 // PasswordAutofillManager, public:
 
@@ -66,13 +109,22 @@ void PasswordAutofillManager::OnAddPasswordFormMapping(
 
 void PasswordAutofillManager::OnShowPasswordSuggestions(
     const autofill::FormFieldData& field,
-    const gfx::RectF& bounds,
-    const std::vector<base::string16>& suggestions,
-    const std::vector<base::string16>& realms) {
-  if (!autofill::IsValidString16Vector(suggestions) ||
-      !autofill::IsValidString16Vector(realms) ||
-      suggestions.size() != realms.size())
+    const base::string16& typed_username,
+    bool show_all,
+    const gfx::RectF& bounds) {
+  std::vector<base::string16> suggestions;
+  std::vector<base::string16> realms;
+  LoginToPasswordInfoMap::const_iterator fill_data_it =
+      login_to_password_info_.find(field);
+  if (fill_data_it == login_to_password_info_.end()) {
+    // TODO(vabr): After https://codereview.chromium.org/686653003/, the only
+    // way to get here should be a compromised renderer.
+    NOTREACHED();
     return;
+  }
+  GetSuggestions(fill_data_it->second, typed_username, &suggestions, &realms,
+                 show_all);
+  DCHECK_EQ(suggestions.size(), realms.size());
 
   form_field_ = field;