4 files changed, 31 insertions, 15 deletions
diff --git a/chrome/browser/autofill/autofill_scanner.cc b/chrome/browser/autofill/autofill_scanner.cc
index 1fd8a7e..41aadc8 100644
--- a/chrome/browser/autofill/autofill_scanner.cc
+++ b/chrome/browser/autofill/autofill_scanner.cc
@@ -10,6 +10,8 @@
 AutofillScanner::AutofillScanner(
     const std::vector<const AutofillField*>& fields)
     : cursor_(fields.begin()),
+      saved_cursor_(fields.begin()),
+      begin_(fields.begin()),
       end_(fields.end()) {
 }
 
@@ -35,11 +37,18 @@ bool AutofillScanner::IsEnd() const {
 }
 
 void AutofillScanner::Rewind() {
-  DCHECK(!saved_cursors_.empty());
-  cursor_ = saved_cursors_.back();
-  saved_cursors_.pop_back();
+  DCHECK(saved_cursor_ != end_);
+  cursor_ = saved_cursor_;
+  saved_cursor_ = end_;
 }
 
-void AutofillScanner::SaveCursor() {
-  saved_cursors_.push_back(cursor_);
+void AutofillScanner::RewindTo(size_t index) {
+  DCHECK(index < static_cast<size_t>(end_ - begin_));
+  cursor_ = begin_ + index;
+  saved_cursor_ = end_;
+}
+
+size_t AutofillScanner::SaveCursor() {
+  saved_cursor_ = cursor_;
+  return static_cast<size_t>(cursor_ - begin_);
 }
diff --git a/chrome/browser/autofill/autofill_scanner.h b/chrome/browser/autofill/autofill_scanner.h
index 789889b..562bab8 100644
--- a/chrome/browser/autofill/autofill_scanner.h
+++ b/chrome/browser/autofill/autofill_scanner.h
@@ -29,19 +29,25 @@ class AutofillScanner {
   // Returns |true| if the cursor has reached the end of the stream.
   bool IsEnd() const;
 
-  // Returns the most recently saved cursor -- see also |SaveCursor()|.
+  // Restores the most recently saved cursor. See also |SaveCursor()|.
   void Rewind();
 
-  // Saves the current cursor position.  Multiple cursor positions can be saved,
-  // with stack ordering semantics.  See also |Rewind()|.
-  void SaveCursor();
+  // Repositions the cursor to the specified |index|. See also |SaveCursor()|.
+  void RewindTo(size_t index);
+
+  // Saves and returns the current cursor position. See also |Rewind()| and
+  // |RewindTo()|.
+  size_t SaveCursor();
 
  private:
   // Indicates the current position in the stream, represented as a vector.
   std::vector<const AutofillField*>::const_iterator cursor_;
 
-  // A stack of saved positions in the stream.
-  std::vector<std::vector<const AutofillField*>::const_iterator> saved_cursors_;
+  // The most recently saved cursor.
+  std::vector<const AutofillField*>::const_iterator saved_cursor_;
+
+  // The beginning pointer for the stream.
+  const std::vector<const AutofillField*>::const_iterator begin_;
 
   // The past-the-end pointer for the stream.
   const std::vector<const AutofillField*>::const_iterator end_;
diff --git a/chrome/browser/autofill/credit_card_field.cc b/chrome/browser/autofill/credit_card_field.cc
index 13f5a89..8d504f4 100644
--- a/chrome/browser/autofill/credit_card_field.cc
+++ b/chrome/browser/autofill/credit_card_field.cc
@@ -27,7 +27,7 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner,
     return NULL;
 
   scoped_ptr<CreditCardField> credit_card_field(new CreditCardField);
-  scanner->SaveCursor();
+  size_t saved_cursor = scanner->SaveCursor();
 
   // Credit card fields can appear in many different orders.
   // We loop until no more credit card related fields are found, see |break| at
@@ -131,7 +131,7 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner,
 
         if (!ParseFieldSpecifics(scanner, pattern, MATCH_DEFAULT | MATCH_SELECT,
                                  &credit_card_field->expiration_year_)) {
-          scanner->Rewind();
+          scanner->RewindTo(saved_cursor);
           return NULL;
         }
         continue;
@@ -179,7 +179,7 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner,
     return credit_card_field.release();
   }
 
-  scanner->Rewind();
+  scanner->RewindTo(saved_cursor);
   return NULL;
 }
 
diff --git a/chrome/browser/autofill/phone_field.cc b/chrome/browser/autofill/phone_field.cc
index 58a7fc8..064dfc6 100644
--- a/chrome/browser/autofill/phone_field.cc
+++ b/chrome/browser/autofill/phone_field.cc
@@ -263,7 +263,6 @@ bool PhoneField::ParseInternal(PhoneField *phone_field,
 
   for (size_t i = 0; i < arraysize(phone_field_grammars_); ++i) {
     memset(parsed_fields, 0, sizeof(parsed_fields));
-    scanner->Rewind();
     scanner->SaveCursor();
 
     // Attempt to parse according to the next grammar.
@@ -300,6 +299,8 @@ bool PhoneField::ParseInternal(PhoneField *phone_field,
       scanner->Rewind();
       return false;  // Tried through all the possibilities - did not match.
     }
+
+    scanner->Rewind();
   }
 
   if (!parsed_fields[FIELD_PHONE]) {