Teach PasswordAutofillAgent sometimes match prefixes of usernames

components/autofill/core/common/autofill_util.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_
 #define COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 38 matching lines @@
 // characters that are part of delimiter set {' ', '.', ',', '-', '_', '@'}.
 
 // Returns true if the |field_contents| is a substring of the |suggestion|
 // starting at token boundaries. |field_contents| can span multiple |suggestion|
 // tokens.
 bool FieldIsSuggestionSubstringStartingOnTokenBoundary(
     const base::string16& suggestion,
     const base::string16& field_contents,
     bool case_sensitive);
 
+// Currently, a token for the purposes of this method is defined as {'@'}.

[vabr (Chromium), 2017/06/19 12:54:15]

nit: Please update the comment not to mention any tokens, just inline '@'.

+// Returns true if the |full_string| has a |prefix| as a prefix and the prefix
+// ends on a token.
+bool IsPrefixOfEmailEndingAtSign(const base::string16& full_string,

[vabr (Chromium), 2017/06/19 12:54:15]

nit: EndingAtSign -> EndingWithAtSign

(The current name has an ambiguous use of "at", let's make clear "At" is meant
as the name of the sign.)

[melandory, 2017/06/21 12:00:42]

Done.

+                                 const base::string16& prefix);
+
 // Finds the first occurrence of a searched substring |field_contents| within
 // the string |suggestion| starting at token boundaries and returns the index to
 // the end of the located substring, or base::string16::npos if the substring is
 // not found. "preview-on-hover" feature is one such use case where the
 // substring |field_contents| may not be found within the string |suggestion|.
 size_t GetTextSelectionStart(const base::string16& suggestion,
                              const base::string16& field_contents,
                              bool case_sensitive);
 
 // Returns true if running on a desktop platform. Any platform that is not
@@ skipping 10 matching lines @@
 
 // Lowercases and tokenizes a given |attribute| string.
 // Considers any ASCII whitespace character as a possible separator.
 // Also ignores empty tokens, resulting in a collapsing of whitespace.
 std::vector<std::string> LowercaseAndTokenizeAttributeString(
     const std::string& attribute);
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_COMMON_AUTOFILL_UTIL_H_