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 33 matching lines @@
 // Returns true if we show a hint in the keyboard accessory suggestions to call
 // attention to the availability of autofill suggestions.
 bool IsHintEnabledInKeyboardAccessory();
 
 // A token is a sequences of contiguous characters separated by any of the
 // 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);
+bool IsSubstringStartingOnTokenBoundary(const base::string16& suggestion,

[vabr (Chromium), 2017/06/12 18:56:58]

nit: I'm not sure what is the advantage of dropping "Field" from the name of
this function. It generates unnecessary churn in the code and confuses per-line
history with unrelated changes. Also the "field" from the name is reflected in
the "field" part of |field_contents|, with the latter making less sense now.

[melandory, 2017/06/19 10:53:48]

I brought old name back

+                                        const base::string16& field_contents,
+                                        bool case_sensitive);
+
+// Currently, a token for the purposes of this method is defined as {'@'}.

[vabr (Chromium), 2017/06/12 18:56:59]

nit: Redefining "token" for this method and keeping the old definition for the
methods above and below is confusing. Also, it is unlikely that more token
separators will be added for this function. I propose replacing "TokenBoundary"
with "AtSign".

[melandory, 2017/06/19 10:53:48]

Done.

+// Returns true if the |full_string| has a |prefix| as a prefix and the prefix
+// ends on a token.
+bool IsPrefixEndingOnTokenBoundary(const base::string16& full_string,
+                                   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);
 
@@ skipping 11 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_